The Marvel Universe is strongly based on the real world. Earth in the Marvel Universe has all the features of the real one: same countries, same personalities (politicians, movie stars, etc.), same historical events (such as World War II), and so on; however, it also contains many other fictional elements: countries such as Wakanda and Latveria and organizations like the espionage agency S.H.I.E.L.D. and its enemies, Hydra and A.I.M. In 2009, Marvel officially described its world's geography in a two-part miniseries, the Marvel Atla. Most importantly, the Marvel Universe also incorporates examples of almost all major science fiction and fantasy concepts, with writers adding more continuously. Aliens, gods, magic, cosmic powers and advanced technology all exist prominently in the Marvel Universe. These extra elements are incorporated simultaneously into the stories, lending to the existence of the superpowered characters. The general public is so familiar with such concepts that Empire State University has a scholarship for "aliens, dimensional travelers, clones, independent machine intelligences and other students outside the norm", businesses and residences have superhero property insurance bookmakers take bets on their battles' outcomes, and New York air traffic controllers handle starships landing at local airports. Heroes and Villains: Within the fictional history of the Marvel Universe, the tradition of using costumed secret identities to fight or commit evil had long existed, but it came into prominence during the days of the American "Wild West" with heroes such as Carter Slade/the Phantom Rider. During the 20th century, the tradition was reinvigorated by Steve Rogers/Captain America and the Invaders in the 1940s, who fought for the Allies of World War II. Unlike the DC Universe, few of Marvel's Golden Age characters have risen to prominence in modern publications; Captain America is one exception, and to a lesser extent, his contemporary, Namor, primarily because both of these characters were reintroduced to readers and the Marvel Universe during the 1960s. Marvel's most prominent heroes were created during the Silver Age of Comic Books in the 1960s to early 1970s, including Spider-Man, Doctor Strange, Daredevil, Nick Fury, the Black Panther, the Silver Surfer, and the early members of the Avengers, X-Men, Fantastic Four, and the Inhumans. The Bronze Age and Modern Age from the early-to-mid 1970s to the early 1990s introduced many new additions to every corner of the Marvel Universe. The comics introduced street heroes such as the Heroes for Hire and the Punisher, space heroes including many members of the future Guardians of the Galaxy and Nova, and supernatural heroes such as Ghost Rider and Blade. New members were added to existing hero teams, including Wolverine, Storm, Kitty Pryde, Colossus, Nightcrawler, Rogue, Psylocke and Dazzler to the X-Men; and Mockingbird, Monica Rambeau, and Tigra to the Avengers. Other notable debuts include Scott Lang, Black Cat, Emma Frost, She-Hulk, Jessica Drew, Elektra, Man Thing, and Moon Knight, and new teams including the New Mutants, Alpha Flight, Eternals, Power Pack and the New Warriors. From the mid-90s to present, Marvel created characters such as Deadpool, Gambit, Cable, Domino, the Thunderbolts, the Runaways, Shuri, Phil Coulson, and Maria Hill. Legacy characters became a popular staple during this time, introducing characters such as X-23, Miles Morales, Yelena Belova, Cassie Lang, Kamala Khan, Kate Bishop, Moon Girl, America Chavez, Robbie Reyes, Ironheart and Spider-Gwen. Prominent teams of superheroes include the Avengers, the X-Men, the Fantastic Four, the Defenders, the Inhumans, S.H.I.E.L.D., the Howling Commandos, the Guardians of the Galaxy, the Runaways, the Midnight Sons and the Thunderbolts. Notable supervillain teams include the Masters of Evil, the Emissaries of Evil, the Brotherhood of Mutants, the Sinister Six, the Frightful Four, the Lethal Legion, the Legion of the Unliving, the Black Order, the Annihilation Wave, and the Cabal. Origin of Superhuman Powers: Most of the superhumans in Marvel's Earth owe their powers to the Celestials, cosmic entities who visited Earth millions of years ago and experimented on their prehistoric ancestors (a process they also carried out on several other planets). This resulted in the creation of two hidden races, the godlike Eternals and the genetically unstable Deviants, in addition to giving some humans an "x-factor" in their genes, which sometimes activates naturally, resulting in sometimes superpowered, sometimes disfigured individuals called mutants. Others require other factors (such as radiation) for their powers to come forth. Depending on the genetic profile, individuals who are exposed to different chemicals or radiation will often suffer death or injury, while in others it will cause superhuman abilities to manifest. Except for psionic abilities, these powers are usually random. It is not clear why the Celestials did this, although it is known that they continue to observe humanity's evolution. A Marvel series titled Earth X explored one possible reason for this: that superhumans are meant to protect a Celestial embryo that grows inside Earth against any planetary threats and have done so for eons. The majority of the public is unaware of what may cause superhuman powers. Some heroes and villains have no powers at all but depend instead on hand-to-hand combat training or advanced technological equipment. In the Marvel Universe, technology is considerably more advanced than in the real world; this is due to unique individuals of genius-level intelligence, such as Reed Richards (Mister Fantastic) of the Fantastic Four. However, most of the advanced devices are too expensive for the common citizen, and are usually in the hands of government organizations like S.H.I.E.L.D., or powerful criminal organizations like A.I.M. Advanced technology has also been given to humans by hidden races, aliens, or time travelers like Kang the Conqueror, who is known to have influenced the robotics industry in the past. The Marvel Universe has a vast number of additional sources of superhuman powers, including cosmic forces (such as the Power Cosmic or Phoenix Force), extra dimensions (such as the Darkforce and Lightforce dimensions), or the many branches of magic. Some races are born with natural powers beyond the means of humans. Races: In Marvel Comics, mutants (Homo superior) are a key source of storytelling and the origins of a number of prominent characters, mostly those in the X-Men universe. Mutants are born with the X-gene, often granting them superhuman abilities and sometimes physical mutations differing them from normal humans. Many people of the Marvel Universe fear or despise mutants, seeing them as dangerous threats. This has caused organizations to form to deal with the problem. Some seek peaceful coexistence between mutants and normal humans (the X-Men and their affiliated groups), those who seek to control or eliminate humans to give mutants safety or dominance (Magneto and his followers, as well as other mutants such as Apocalypse), and those who seek to regulate or eliminate mutants in favor of humans. In addition to mutants, Eternals, and Deviants, several other intelligent races have existed secretly on Earth. These include the Inhumans, another genetically unstable race (like the Deviants, but in their case, it is due to their use of a substance called the Terrigen Mist) that was created by a Kree experiment long ago; the Subterraneans, a race of humanoids adapted to living below the surface, created by the Deviants (some Subterraneans were transformed into the 'Lava Men' by a demon); and Homo mermanus, a humanoid species of water-breathers that live in Earth's oceans. Most of these races have advanced technology but existed hidden from humanity until recent times. More variants of humanity can be found in the Savage Land. Most of the Savage Land races have their origin from a group of primitive ape-men who seems to have escaped the Celestial experiments and whose influence is present in all modern Homo sapiens. Other leftovers from the era when primitive humanoids walked on Earth still exist, such as the radiation-altered Neanderthal man known as the Missing Link, an enemy of the Hulk. Supernatural Creatures: Also abundant in the Marvel Universe are legendary creatures such as gods, demons and vampires. The 'gods' of most polytheistic pantheons are powerful, immortal human-like races residing in other dimensions who visited Earth in ancient times, and became the basis of many legends. However, all of these 'gods' share a common ancestry and connection to Earth due to Gaea, the primeval Elder Goddess that infused her life essence into all living things on Earth. Besides mythological gods, many deities made up by Marvel writers exist as well, such as the Dark Gods, enemies of the Asgardians. Angels and demons have appeared throughout the franchise, with some form of Heaven and Hell existing on other planes in the Universe. Some notable demons include Blackheart, Mephisto, Nightmare, and Satannish. There are also powerful benevolent mystical entities such as the Vishanti; or amoral and malevolent entities who are not truly demonic, such as Dormammu and the Octessence, or ones heavily drawing upon the mythologies of H. P. Lovecraft and Robert E. Howard. Some supernatural beings, entities and human characters created by Lovecraft and Howard, who were friends and influenced each other's work, have been adapted by Marvel and include Abdul Alhazred, Conan the Barbarian, Nyarlathotep and Set. Some deities or demonic beings that are original characters of Marvel have been heavily influenced by these mythologies, such as Shuma-Gorath.[32] Most of the current generation of gods have been revealed to be the descendants of the Elder Goddess Gaea. The two most featured pantheons are the Asgardians (of whom Thor is a member) and the Olympians (of whom Hercules is a member). The lords of the various pantheons sometimes gather in groups known as either the Council of Godheads or the Council of Skyfathers. The gods were forced to stop meddling with humanity (at least openly) a thousand years ago by the Celestials, and most people today believe them to be fictional. Other pantheons have been depicted in the Marvel Universe that is still actively worshiped in the real world, including those worshiped by the Aboriginal inhabitants of Australia, the gods of Hinduism, the Shinto gods and the gods of Zoroastrianism. These deities are rarely depicted, however. To avoid offending the believers of still active religions, Marvel features such deities as characters in the background or who make very brief cameo appearances. The Marvel Universe also contains a number of monsters. Classic monsters such as vampires, werewolves, ghosts, and zombies all exist within the Universe, as well as fictional monster races. Monsters were prominent in early publications such as Journey into Mystery and Strange Tales. Cosmic Entities: The cosmic entities are beings of unbelievably great levels of power (the weakest of whom can destroy entire planets) who exist to perform duties that maintain the existence of the universe. Most do not care at all about "lesser beings" such as humans, and as a consequence, their acts are recurrently dangerous to mortals. When dire threats threaten the universe, it is not uncommon for these beings to gather together to discuss the threat and even act on it. Most conceptual entities are simply interested in furthering their essential function or to keep the balance with an opposing force. However, certain cosmic entities, such as Galactus, the In-Betweener, the Maelstrom, or the Stranger have demonstrated personality, motivations, or (except for the first one mentioned) even ambitions beyond their functions, but often maintain the perspective that morality is entirely relative, or that destroying civilizations of "lesser" beings is no eviler than if these beings destroyed an anthill. Others such as Uatu the Watcher, Eon, or the Celestials, Ashema and Tiamut are aberrations in the sense of sympathizing with, and occasionally coming to the defense of, humanity. The Phoenix Force is composed of the psionic energy from all living beings' past, present, and future, and is an embodiment of rebirth and destructive transformation through "burning away what doesn't work", and helped to restart the universe before the Big Bang. 'The "Fulcrum" is a comparatively recent addition to the hierarchy, that "all" cosmic entities allegedly serve, of a level of raw power stated to far surpass the might of the Watchers and the Celestials. Unlike most other entities, it is capable of conscience, compassion, and even a sense of humor, and has stated that it wants other cosmic beings to develop such as well. He is a possible manifestation/avatar of the One-Above-All. The mentioned One-Above-All is believed to be the supreme, omnipotent being, who solely created the Marvel Multiverse, and possibly acted beyond. He also brought to life the Living Tribunal, an extremely powerful cosmic entity, who serves to maintain balance within the Multiverse.