The War of the Worlds is a science fiction novel by English author H. G. Wells. It was written between 1895 and 1897, and serialised in Pearson's Magazine in the UK and Cosmopolitan magazine in the US in 1897. The full novel was first published in hardcover in 1898 by William Heinemann. The War of the Worlds is one of the earliest stories to detail a conflict between humankind and an extraterrestrial race. The novel is the first-person narrative of an unnamed protagonist in Surrey and his younger brother in London as southern England is invaded by Martians. It is one of the most commented-on works in the science fiction canon.
The plot is similar to other works of invasion literature from the same period, and has been variously interpreted as a commentary on the theory of evolution, imperialism, and Victorian era fears, superstitions and prejudices. Wells later noted that inspiration for the plot was the catastrophic effect of European colonisation on the Aboriginal Tasmanians. Some historians have argued that Wells wrote the book to encourage his readership to question the morality of imperialism. At the time of publication, it was classified as a scientific romance, like Wells's earlier novel, The Time Machine.
The War of the Worlds has been both popular (having never been out of print) and influential, spawning numerous feature films, radio dramas, a record album, comic book adaptations, television series, and sequels or parallel stories by other authors. It was memorably dramatised in a 1938 radio programme, directed by and starring Orson Welles, that reportedly caused panic among listeners who did not know that the events were fictional. The novel even influenced the work of scientists. Robert H. Goddard was inspired by the book, and helped develop both the liquid-fuelled rocket and multistage rocket, which resulted in the Apollo 11 Moon landing 71 years later.
Plot
Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us.
— H. G. Wells (1898), The War of the Worlds
The coming of the Martians
The novel opens in the mid-1890s, with aliens on Mars plotting an invasion of Earth because their resources were dwindling. The main narrative ("The Great Disillusionment") takes place in the early 20th century, in the summer, when an object thought to be a meteor lands on Horsell Common, near the narrator's home. It turns out to be an artificial cylinder that was launched towards Earth several months earlier as Earth and Mars approached opposition. Martians emerge briefly, but have difficulty coping with Earth's atmosphere and gravity. When humans approach the cylinder with a white flag, the Martians incinerate them using a heat ray. Military forces arrive that night.
The next day, the narrator takes his wife to safety in Leatherhead by means of a dog-cart rented from the local pub landlord, but returns home by himself immediately after in order to return the vehicle. That night, he sees a three-legged Martian "fighting-machine" (tripod), armed with a heat-ray and a chemical weapon: the poisonous "black smoke". Tripods have wiped out the army around the cylinder and destroyed most of Woking. The narrator approaches his own house and finds the landlord dead in the front garden, killed by a Martian attack. While keeping watch from an upper floor window, he offers shelter to an artilleryman who has fled after his company was wiped out attacking the cylinder. The narrator and the artilleryman try to escape back towards Leatherhead, but are separated during a Martian attack between Shepperton and Weybridge. As refugees try to cross the River Wey, the army destroys a tripod with artillery fire, and the Martians retreat. The narrator travels to Walton, where he meets a curate.
The Martians attack again and people begin to flee London, including the narrator's brother, who travels with a Mrs Elphinstone and her sister-in-law to keep them safe. They reach the coast and buy passage to Continental Europe. Tripods attack, but a torpedo ram, HMS Thunder Child, destroys two of them before being destroyed itself (a third is either destroyed in the detonation of the ship ammunition stores, or flees unseen in the resultant smoke), and the evacuation fleet escapes. Soon, all organised resistance collapses, and Martians roam the shattered landscape unhindered.
The Earth under the Martians
At the beginning of Book Two, the narrator and the curate witness a Martian machine seizing people and tossing them into a carrier. The narrator realises that the Martian invaders may have plans for their victims. When a fifth Martian cylinder lands, both men are trapped beneath the ruins of a house. The narrator describes Martian anatomy and how they use living creatures' blood to nourish themselves. The two men's relationship deteriorates, and eventually, the narrator knocks the curate unconscious. A Martian removes the curate's body, but the narrator escapes detection.
The Martians abandon the cylinder's crater, and the narrator emerges from the collapsed house and heads for West London. En route, he finds Martian red weed everywhere, prickly vegetation spreading wherever there is abundant water, but slowly dying. On Putney Heath, he encounters the artilleryman again. After abandoning him, he begins to go mad from his trauma, finally attempting suicide by approaching a stationary fighting machine on Primrose Hill. To his surprise, he discovers that all the Martians have been killed by an onslaught of earthly pathogens, to which they had no immunity.
The narrator suffers a nervous breakdown and is nursed back to health by a kind family. Eventually, he returns to Woking, and discovers that his wife has survived. In the last chapter, he reflects on the Martian invasion, its impact on humanity's view of itself and the future, and the effect it has had on his mind.
Background
Style
The War of the Worlds presents itself as a factual account of the Martian invasion. It is considered one of the first works to theorise the existence of a race intelligent enough to invade Earth. The narrator is a middle-class writer of philosophical papers, reminiscent of Doctor Kemp in The Invisible Man, with characteristics similar to author Wells at the time of writing. The reader learns little about the background of the narrator or indeed of anyone else in the novel; characterisation is unimportant. In fact, few of the principal characters are named, aside from the astronomer Ogilvy and Miss and Mrs Elphinstone.
Scientific setting
Wells was trained as a science teacher during the latter half of the 1880s. One of his teachers was Thomas Henry Huxley, a major advocate of Darwinism. Wells later taught science, and his first book was a biology textbook. Much of his work is notable for making contemporary ideas of science and technology easily understandable.
The scientific fascinations of the novel are established in the opening chapter. The narrator views Mars through a telescope, and Wells offers the image of the superior Martians having observed human affairs, as though watching tiny organisms through a microscope. In August 1894, a French astronomer reported sightings of a "strange light" on Mars. Wells used this observation to open the novel, imagining these lights to be the launching of the Martian cylinders toward Earth.
Italian astronomer Giovanni Schiaparelli observed features on Mars in 1878, which he called canali (Italian for "channels"). In 1895, American astronomer Percival Lowell speculated in his book Mars that these might be irrigation channels, constructed by a sentient life form to support existence on an arid, dying world. The novel also explores ideas related to Charles Darwin's theory of natural selection.
In 1896, Wells published an essay on 'Intelligence on Mars' in the Saturday Review, setting out ideas about life on Mars. Wells speculates on the nature of Martian inhabitants and how their evolutionary progress might compare to humans. These ideas are used almost unchanged in The War of the Worlds.
Wells has also imagined how life could evolve in hostile conditions, like those on Mars. The creatures have no digestive system, no appendages except tentacles and put the blood of other beings in their veins to survive. Wells was writing some years before Karl Landsteiner discovered the three human blood groups (O, A, and B), and showed the challenges of even transfusing blood between humans with incompatible blood groups.
Physical location
In 1895, Wells married Catherine Robbins, and moved with her to Woking in Surrey. There, he spent his mornings walking or cycling in the countryside, and his afternoons writing. The original idea for The War of the Worlds came from his brother during one of these walks, pondering on what it might be like if alien beings were suddenly to descend on the scene. A 23 feet (7.0 m) high sculpture of a tripod fighting machine, entitled The Woking Martian, based on descriptions in the novel stands in Crown Passage close to the local railway station in Woking, designed and constructed in 1998 by artist Michael Condron. Fifty meters further up the pedestrianised street is a concrete and brick representation of a Martian cylinder.
Cultural setting
Wells's depiction of late Victorian suburban culture in the novel was an accurate representation of his own experiences at the time. In the late 19th century, the British Empire was the predominant colonial power on the globe, making its domestic heart a poignant and terrifying starting point for an invasion by Martians with their own imperialist agenda. Wells also drew on a common fear that emerged in the years approaching the turn of the century, known as the fin de siècle or 'end of the age', which anticipated an apocalypse occurring at midnight on the last day of 1899.
Publication
In the late 1890s it was common for novels to be serialised in magazines or newspapers before publication in full, with each part of the serialisation ending on a cliffhanger to entice audiences to buy the next issue. This practice was familiar from Charles Dickens's novels earlier in the nineteenth century. The War of the Worlds was first serialised in the United Kingdom in Pearson's Magazine from April to December 1897. Wells was paid £200 and Pearsons demanded to know the ending of the piece before committing to publish. The complete volume was first published by Heinemann in 1898 and has been in print ever since.
Two unauthorised serialisations of the novel were published in the United States prior to publication of the novel. The first was in the New York Evening Journal where the story was published as Fighters from Mars or the War of the Worlds, located in a New York setting, between December 1897 and January 1898. The second version had the Martians landing near and around Boston, and was published by The Boston Post as Fighters from Mars, or the War of the Worlds in and near Boston in 1898. Even though these versions are considered unauthorised, Hughes and Geduld speculate that Wells may inadvertently have agreed to the serialisation in the New York Evening Journal. These two versions of the story were followed by Edison's Conquest of Mars by Garrett P. Serviss.
Holt, Rinehart & Winston reprinted the book in 2000, paired with The Time Machine, and commissioned Michael Koelsch to illustrate a new cover art.
Reception
The War of the Worlds was received favourably by both readers and critics. The Illustrated London News wrote that the serialisation in Pearson’s magazine had "a very distinct success". The story did even better as a book, and reviewers rated it as "the very best work he has yet produced", and highlighting the story's originality in showing Mars in a new light through the concept of an alien invasion of Earth. Writing for Harper's Weekly, Sidney Brooks admired Wells's writing style: "he has complete check over his imagination, and makes it effective by turning his most horrible of fancies into the language of the simplest, least startling denomination". Praising Wells's "power of vivid realization", The Daily News reviewer wrote, "the imagination, the extraordinary power of presentation, the moral significance of the book cannot be contested". There was, however, some criticism of the brutal nature of the events in the narrative.
Invasion literature
Between 1871 and 1914 more than 60 works of fiction for adult readers describing invasions of Great Britain were published. The original work was The Battle of Dorking (1871) by George Tomkyns Chesney, which portrays a surprise German attack and landing on the south coast of England, made possible by the distraction of the Royal Navy in colonial patrols and the army in an Irish insurrection. The German army makes short work of English militia and rapidly marches to London. This story was published in Blackwood's Magazine in May 1871 and was so popular that it was reprinted a month later as a pamphlet which sold 80,000 copies.
There are clear plot similarities between Wells's book and The Battle of Dorking. In both, a ruthless enemy makes a devastating surprise attack, with the British armed forces helpless to stop its relentless advance; and both involve the destruction of the Home Counties of southern England. However The War of the Worlds transcends the typical fascination of invasion literature with European politics and international disputes, with its introduction of an alien adversary.
The invasion literature genre provided a familiar base from which to support the success of The War of the Worlds. It may also have proved an important foundation for Wells's ideas, as he had never seen or fought in a war.
Scientific predictions and accuracy
Mars
Many novels focusing on life on other planets written close to 1900 echo scientific ideas of the time, including Pierre-Simon Laplace's nebular hypothesis, Charles Darwin's scientific theory of natural selection, and Gustav Kirchhoff's theory of spectroscopy. These ideas combined to present the possibility that planets are alike in composition and conditions for the development of species, which would likely lead to the emergence of life at a suitable geological age in a planet's development.
By the time Wells wrote The War of the Worlds, there had been three centuries of observation of Mars through telescopes. Galileo observed the planet's phases in 1610 and in 1666 Giovanni Cassini identified the polar ice caps. In 1878 Italian astronomer Giovanni Schiaparelli observed geological features which he called canali (Italian for "channels"). This was mistranslated into English as "canals" which, being artificial watercourses, fuelled the belief in intelligent extraterrestrial life on the planet. This influenced American astronomer Percival Lowell. In 1895 Lowell's book Mars speculated about an arid, dying landscape, whose inhabitants built canals to bring water from the polar caps to irrigate the remaining arable land. This encapsulated contemporary scientific ideas about conditions on the red planet at the time The War of the Worlds was written; ideas which persisted until they were tested by space missions, starting with the Viking program, that found a lifeless world too cold for liquid water to exist.
Space travel
The Martians travel to the Earth in cylinders, apparently fired from a huge space gun on the surface of Mars. This was a common representation of space travel in the nineteenth century, and had also been used by Jules Verne in From the Earth to the Moon. Modern scientific understanding renders this idea impractical, as it would be difficult to control the trajectory of the gun precisely, and the force of the explosion necessary to propel the cylinder from the Martian surface to the Earth would likely kill the occupants., however there has been renewed interest in this type of launch system in recent years with several space agencies conducting feasibility studies into space gun type launch system, particularly the use of electromagnetic rail gun technology.
The 16-year-old Robert H. Goddard was inspired by the story and spent much of his life building rockets. The work of the German rocket scientists Hermann Oberth and his student Wernher von Braun led to the V-2 rocket becoming the first artificial object to travel into space by crossing the Kármán line on 20 June 1944, and rocket developments culminated in the Apollo program's human landing on the Moon, and the landing of robotic probes on Mars.
Total war
The Martian invasion's principal weapons are the Heat-Ray and the poisonous Black Smoke. Their strategy includes the destruction of infrastructure such as armament stores, railways, and telegraph lines; it appears to be intended to cause maximum casualties, leaving humans without any will to resist. These tactics became more common as the twentieth century progressed, particularly during the 1930s with the development of mobile weapons and technology capable of surgical strikes on key military and civilian targets.
Wells's vision of a war bringing total destruction without moral limitations in The War of the Worlds was not taken seriously by readers at the time of publication. He later expanded these ideas in the novels When the Sleeper Wakes (1899), The War in the Air (1908), and The World Set Free (1914). This kind of total war did not become fully realised until the Second World War.
Critic Howard Black wrote that "In concrete details the Martian Fighting Machines as depicted by Wells have nothing in common with tanks or dive bombers, but the tactical and strategic use made of them is strikingly reminiscent of Blitzkrieg as it would be developed by the German armed forces four decades later. The description of the Martians advancing inexorably, at lightning speed, towards London; the British Army completely unable to put up an effective resistance; the British government disintegrating and evacuating the capital; the mass of terrified refugees clogging the roads, all were to be precisely enacted in real life at 1940 France." Black regarded this 1898 depiction as far closer to the actual land fighting of World War II than Wells's much later work The Shape of Things to Come (1933).
Weapons and armour
Wells's description of chemical weapons – the Black Smoke used by the Martian fighting machines to kill human beings in great numbers – became a reality in World War I. The comparison between lasers and the Heat-Ray was made as early as the later half of the 1950s when lasers were still in development. Prototypes of mobile laser weapons have been developed and are being researched and tested as a possible future weapon in space.
Military theorists of the era, including those of the Royal Navy prior to the First World War, had speculated about building a "fighting-machine" or a "land dreadnought". Wells later further explored the ideas of an armoured fighting vehicle in his short story "The Land Ironclads". There is a high level of science fiction abstraction in Wells's description of Martian automotive technology; he stresses how Martian machinery is devoid of wheels. They use "a complicated system of sliding parts" to produce movement, possess multiple whip-like tentacles for grasping, and paralleling animal motion, "quasi-muscles abounded in the crablike handling machine".
Interpretations
Natural selection
.jpg)
H. G. Wells was a student of Thomas Henry Huxley, a proponent of the theory of natural selection. In the novel, the conflict between humankind and the Martians is portrayed as a survival of the fittest, with the Martians whose longer period of successful evolution on the older Mars has led to them developing a superior intelligence, able to create weapons far in advance of humans on the younger planet Earth, who have not had the opportunity to develop sufficient intelligence to construct similar weapons.
Human evolution
The novel also suggests a potential future for human evolution and perhaps a warning against overvaluing intelligence against more human qualities. The Narrator describes the Martians as having evolved an overdeveloped brain, which has left them with cumbersome bodies, with increased intelligence, but a diminished ability to use their emotions, something Wells attributes to bodily function.
The Narrator refers to an 1893 publication suggesting that the evolution of the human brain might outstrip the development of the body, and organs such as the stomach, nose, teeth, and hair would wither, leaving humans as thinking machines, needing mechanical devices much like the Tripod fighting machines, to be able to interact with their environment. This publication is probably Wells's own "The Man of the Year Million", first published in The Pall Mall Gazette on 6 November 1893, which suggests similar ideas.
Colonialism and imperialism
At the time of the novel's publication, the British Empire consisted of roughly a quarter of the world's territories, and a relative period of peace known as the Pax Britannica existed between the great powers of the Western world. Between 1815 and 1914, around 26,000,000 square kilometres (10,000,000 sq mi) of territory and roughly 400 million people were added to the British Empire.
While invasion literature had provided an imaginative foundation for the idea of the heart of the British Empire being conquered by foreign forces, it was not until The War of the Worlds that the British public was presented with an adversary completely superior to themselves. A significant motivating force behind the success of the British Empire was its use of sophisticated technology; the Martians, also attempting to establish an empire on Earth, have technology superior to their British adversaries. In The War of the Worlds, Wells depicted an imperial power as the victim of imperial aggression, and thus perhaps encouraging the reader to consider the morality of imperialism itself.
Wells suggests this idea in the following passage:
And before we judge them [the Martians] too harshly, we must remember what ruthless and utter destruction our own species has wrought, not only upon animals, such as the vanished Bison and the Dodo, but upon its own inferior races. The Tasmanians, in spite of their human likeness, were entirely swept out of existence in a war of extermination waged by European immigrants, in the space of fifty years. Are we such apostles of mercy as to complain if the Martians warred in the same spirit?
— Chapter I, "The Eve of the War"
Social Darwinism
The novel dramatises the ideas of race presented in Social Darwinism, in that the more advanced Martians exercise their 'rights' as a superior race over humans. Social Darwinism implied that the success of different ethnic groups in world affairs, and social classes in a society, were the result of evolutionary struggle in which the group or class more fit to succeed did so. In more recent times, the use to such arguments to justify the position of the rich and powerful, or dominant groups is regarded as dubious at best.
Wells grew up in a society where the merit of an individual was not considered as important as their social class. His father was a professional sportsman, and seen as inferior to 'gentle' status. His mother was a domestic servant, and Wells himself was initially apprenticed to a draper. As a scientist, he was able to relate his experiences of struggle to Darwin's idea of a world of struggle; but saw science as a rational system, which extended beyond traditional ideas of race, class and religious notions, and in his fiction challenged the use of science to explain political and social norms of the day.
Religion and science
Good and evil appear relative in The War of the Worlds, and the defeat of the Martians has an entirely material cause: the action of microscopic bacteria. An insane clergyman is important in the novel, but his attempts to relate the invasion to Armageddon seem examples of his mental derangement. His death, as a result of his evangelical outbursts and ravings attracting the attention of the Martians, appears an indictment of his obsolete religious attitudes; but the Narrator twice prays to God, and suggests that bacteria may have been divinely allowed to exist on Earth for a reason such as this, suggesting a more nuanced critique.
Influences
Mars and Martians
The novel initiated several enduring Martian tropes in science fiction writing. These include Mars being an ancient world; nearing the end of its life; being the home of a superior civilisation capable of advanced feats of science and engineering; and also being a source of invasion forces, keen to conquer the Earth. The first two tropes were prominent in Edgar Rice Burroughs's "Barsoom" series beginning with A Princess of Mars in 1912.
Physicist Freeman Dyson, a key figure in the search for extraterrestrial life, acknowledged his debt to reading H. G. Wells's fictions as a child.
The publication and reception of The War of the Worlds established the vernacular term of 'martian' as a description for something offworldly or unknown.
Aliens and alien invasion
Antecedents
Wells is credited with establishing several extraterrestrial themes which were later greatly expanded by science fiction writers in the 20th century, including first contact and war between planets and their differing species. There were, however, stories of aliens and alien invasion prior to the publication of The War of the Worlds.
In 1727 Jonathan Swift published Gulliver's Travels. The tale included a people who are obsessed with mathematics and more advanced than Europeans scientifically. They populate a floating island fortress called Laputa, 4½ miles in diameter, which uses its shadow to prevent sun and rain from reaching earthly nations over which it travels, ensuring they will pay tribute to the Laputians.
Voltaire's Micromégas (1752) includes two beings from Saturn and Sirius who, though human in appearance, are of immense size and visit the Earth out of curiosity. At first the difference in scale between them and the peoples of Earth makes them think the planet is uninhabited. When they discover the haughty Earth-centric views of Earth philosophers, they are greatly amused by how important Earth beings think they are compared to greater beings in the universe such as themselves.
In 1892 Robert Potter, an Australian clergyman, published The Germ Growers in London. It describes a covert invasion by aliens who take on the appearance of human beings and attempt to develop a virulent disease to assist in their plans for global conquest. It was not widely read, and consequently Wells's vastly more successful novel is generally credited as the seminal alien invasion story.
The first science fiction to be set on Mars may be Across the Zodiac: The Story of a Wrecked Record (1880) by Percy Greg. It was a long-winded book concerned with a civil war on Mars. Another Mars novel, this time dealing with benevolent Martians coming to Earth to give humankind the benefit of their advanced knowledge, was published in 1897 by Kurd Lasswitz – Two Planets (Auf Zwei Planeten). It was not translated until 1971, and thus may not have influenced Wells, although it did depict a Mars influenced by the ideas of Percival Lowell.
Other examples are Hugh MacColl's Mr. Stranger's Sealed Packet (1889), which took place on Mars, Gustavus W. Pope's Journey to Mars (1894), and Pharaoh's Broker by Elmer Dwiggins, writing under the name of Ellsworth Douglass, in which the protagonist encounters an Egyptian civilisation on Mars which, while parallel to that of the Earth, has evolved somehow independently.
Early examples of influence on science fiction
Wells had already proposed another outcome for the alien invasion story in The War of the Worlds. When the Narrator meets the artilleryman the second time, the artilleryman imagines a future where humanity, hiding underground in sewers and tunnels, conducts a guerrilla war, fighting against the Martians for generations to come, and eventually, after learning how to duplicate Martian weapon technology, destroys the invaders and takes back the Earth.
Six weeks after the publication of the novel, The Boston Post newspaper published another alien invasion story, an unauthorised sequel to The War of the Worlds, which turned the tables on the invaders. Edison's Conquest of Mars was written by Garrett P. Serviss, a now little-remembered writer, who described the inventor Thomas Edison leading a counterattack against the invaders on their home soil. Though this is actually a sequel to Fighters from Mars, a revised and unauthorised reprint of The War of the Worlds, they both were first printed in the Boston Post in 1898. Lazar Lagin published Major Well Andyou in the USSR in 1962, an alternative view of events in The War of the Worlds from the viewpoint of a traitor.
The War of the Worlds was reprinted in the United States in 1927, before the Golden Age of science fiction, by Hugo Gernsback in Amazing Stories. John W. Campbell, another key science fiction editor of the era, and periodic short story writer, published several alien invasion stories in the 1930s. Many well-known science fiction writers were to follow, including Isaac Asimov, Arthur C. Clarke, Clifford D. Simak and Robert A. Heinlein with The Puppet Masters and John Wyndham with The Kraken Wakes.
Later examples
The theme of alien invasion has remained popular to the present day and is frequently used in the plots of movies, television, novels, comics and video games. Alan Moore's graphic novel, The League of Extraordinary Gentlemen, Volume II, retells the events in The War of the Worlds.
Tripods
Adaptations
As of 2023, The War of the Worlds has inspired seven films, as well as various radio dramas, comics, video games, television series, and sequels or parallel stories by other authors. Most are set in different locations or eras to the original novel. Among the adaptations is the 1938 radio broadcast narrated and directed by Orson Welles. The first two-thirds of the 60-minute broadcast were presented as a series of news bulletins, often described as having led to outrage and panic by listeners who believed the events described in the program to be real. However, later critics pointed out that the supposed panic was exaggerated by newspapers of the time, seeking to discredit radio as a source of news and information or exploit racial stereotypes.
The first film adaptation was The War of the Worlds, produced in 1953 by George Pal, directed by Byron Haskin, and starring Gene Barry. In 2005, Steven Spielberg directed another film version, starring Tom Cruise.
In 1978, Jeff Wayne produced a musical album of the story, with the voices of Richard Burton and David Essex. Wayne has also toured two live concert musical versions.
An immersive experience of The War of the Worlds set to Jeff Wayne's score opened in London in 2019. Jason Donovan and Carrie Hope-Fletcher attended the world preview on 30 May. The show uses a ground breaking interactive blend of virtual reality, volumetric holograms and live theatre to take visitors into the heart of this classic science fiction story like never before. The show heavily features Jeff Wayne's award-winning musical score as well as holographic performances by Tom Brittney, Anna-Marie Wayne and Carrie Hope Fletcher, a 10-metre slide, the smell of burning flesh and a virtual reality hot air balloon flight to Mars. The show is part of a night out experience where visitors can sample steampunk inspired cocktails and food all set within Victorian Britain in The Spirit of Man Bar.
![3D IC components. Master and the slave boards.[15]](https://en.wikipedia.org/wiki/File:3DS_die_stacking_concept_model.PNG)
![Atmo-vortex engines.[16] Vortex generators](https://en.wikipedia.org/wiki/File:Conceptual_vortex_engine.jpg)
.jpg)
