Sub-Terra

Throughout history, humanity has believed other lands or even entire other worlds lay hidden beneath the surface of the Earth. From mysterious caverns inhabited by monsters to the realms of the dead and the damned, people have speculated about the world within the Earth.
On Earth-Prime that “world” is called Sub-Terra, and is in many ways far stranger than the civilizations on the surface of the Earth have ever imagined. Even in the modern age, it is a place of monsters, myth, and menaces spawned from both science and sorcery.

THE HISTORY OF SUB-TERRA

The ancient empire of the Serpent People discovered the existence of Sub-Terra long before human civilization arose on Earth. It remains unknown if the Serpent People were involved in engineering or creating aspects of the subterranean world, or if they simply discovered and exploited a natural property of Earth’s mystical and dimensional fields. Both have been proclaimed true at different points, but the Serpent People are both mad and notorious liars.
At least initially, the Serpent People had little use for the subterranean realm, primarily using it as a dumpingground for some of their various genetic experiments. Occasional escapees amongst the slaves of the Serpent Empire also found their way into the tunnels and chambers of Sub-Terra. Although most did not survive for long, some did, and a few even managed to thrive there for a time.
Most of the Serpent People perished in the sinking of Lemuria, but some escaped into the subterranean tunnels, deep beneath the surface of the Earth, protected from the devastation of the world above. There the survivors set about creating a new slave race to serve their needs. They engineered a breed of human with great physical strength and the ability to operate in near-total darkness.
These new slaves eventually rebelled against their serpent masters. They seized several underground cities for themselves, expelling the Serpent People from them. The former slaves became known as the Morlocks. Legends about the Morlocks may have inspired various human myths of dark elves, dwarves, mole-people, and other underground dwellers, as well as the work of H.G. Wells in his novel The Time Machine.
In time, the Serpent People engineered a new servitor race, carefully weeding out individual initiative or any ability to rebel. These new slaves, while controllable, proved no match for the savagery of the Morlocks, whose continued attacks against the Serpent People drove them to abandon many of their subterranean settlements, and their new slaves along with them. Without any real initiative of their own, the servile Sub-Terrans continued maintaining the ancient cities and machines, going about their duties without really knowing (or caring) why they did so.
The conflict between the Morlocks and the Serpent People exhausted both societies and drove them both deeper into barbarism. The Serpent People continued to degenerate, until they lost nearly all vestiges of civilization. Cults worshiping terrible, alien gods and practicing profane rites flourished in both cultures, contributing to their decline.
Some years ago Jerris Trent, a surface world explorer, discovered Sub-Terra and some of its Sub-Terran inhabitants. The servile creatures fixated on Trent as their new master and he established his own underground empire (also known as Sub-Terra), dubbing himself the Terra-King. Using the ancient, abandoned science of the Serpent People and his legions of Sub-Terran slaves, the Terra-King has made several attempts to conquer parts of the surface world, thwarted by heroes like the Attom Family and Dr. Metropolis.
Few other surface people have visited Sub-Terra, but the Atom Family spent some time there, as have a few other heroes and explorers. Dr. Atom reports there are thousands of miles of caves and tunnels winding beneath the North American continent alone.

SUB-TERRAN LOCATIONS

As mentioned under Sub-Terran Geography, locations within Sub-Terra often seem to shift, making them difficult to find for everyone except native creatures, which seem to have some type of innate sense of direction.
Among other things, this means that while there are common entrances and ways of accessing the following locations, they’re not always consistent, and an underground tunnel in, say, Freedom City or Emerald City could well connect up with Agartha, Pyros, or even Lemuria with relative ease, turning into a mundane passageway or dead-end when the heroes next investigate it.

AGARTHA

Terra-King named the Sub-Terran ruin he claimed as the center of his “kingdom” Agartha, after the legendary city said to exist at the center of the Earth. Its original name is long since lost, although it was likely originally built by the Serpent People after the sinking of Lemuria and their retreat into Sub-Terra. By the time the Terra-King discovered it, Agartha was a vast ruin barely maintained by the former Sub-Terran slaves of the Serpent People. The majority of the city occupies a single vast cavern, ringed by a high ledge overlooking it. The cavern floor has numerous stone structures, with two broad avenues intersecting at massive stone step-pyramid in the center, which Terra-King claimed as his fortress and throne chamber. A few of the surrounding structures serve as laboratories or storage, while the rest are quarters for the Sub-Terrans or simply left empty, giving the whole of the city a dark, haunted feel. Since neither the Sub-Terrans nor Terra-King require much, if any light, Agartha remains in darkness most of the time. Passages up along the ledge overlooking the cavern find their way out into the tunnels of Sub-Terra. A waterfall cascades over the ledge, tumbling down into a small lake in one quarter of the city, known as the Lake of Shadows, which provides water for Agartha. The depths of the lake flow out into Sub-Terran streams, and serve as a passage for aquatic creatures.

BOCA TIERRA

As detailed in The United States of America, the Boca Tierra Caverns in New Mexico are a fairly stable entrance into the tunnels of Sub-Terra, where its inhabitants find thier way to the surface, the prime reason why the government research facility there was abandoned. The surface entrance to the caverns is carefully monitored by AEGIS and U.S. authorities on the lookout for any signs of Sub-Terran incursion.

LEMURIA

The island continent of Lemuria once existed in the Pacific Ocean thousands of years ago. It was the center of an ancient empire ruled by the Serpent People. The Serpent Empire of Lemuria was old even before modern humans first appeared, and humanity was little more than a curiosity to the saturnine Serpent People. They kept humans as pets and slaves, occasionally using them in their arcane experiments. Saurian scientists genetically-engineered various sub-species of humanity to serve them.
In time, the decadent Lemurian Serpent People came into conflict with the advanced human empire of Atlantis. They fought a long series of wars, which culminated in their mutual annihilation. Lemuria sank beneath the ocean in a terrible cataclysm, spelling the end for the Serpent Empire.
The ruins of Lemuria lie at the bottom of the Pacific Ocean, largely undisturbed, although occasionally visited by scavengers (human and otherwise) looking for ancient artifacts and secrets left behind by the Serpent Empire. Some scattered tribes of Deep Ones are found amongst the underwater ruins, worshipping some lost idol. There are ancient passages from Lemuria to Sub-Terra and some of the aquatic ruins still have breathable pockets of air (likely maintained by some ancient machinery or magic).
Lemuria makes undersea links to Sub-Terra the most common in the Pacific Ocean. Offshore drilling sometimes breaks through into a Sub-Terran pocket, causing floods and terrible damage, and stirring up an attack by creatures like the Magmin or a giant creature.

KAIJU ISLAND

Kaiju Island has underground connections to Sub-Terra, and many of the creatures found on the island may have originated in Sub-Terra or vice versa.

THE MAZE

A vast network of relatively narrow and winding tunnels, the Maze epitomizes the strange nature of Sub-Terra, seemingly home to an infinite variety of oddities. No one knows exactly how far the Maze extends, nor all that it contains. It has been the site of numerous conflicts over the course of millennia, such that its corridors and some of its rooms are filled with various traps and the remains of garrisons or hold-outs belonging to the Serpent People, the Morlocks, the mutant Fomori, and others long since forgotten.
Like other parts of Sub-Terra, sections of the Maze appear to extend into or connect up with different dimensions. At least part of the network lies beneath the cairn-strewn hills of the Blackfell Forest outside a medieval fantasy city known as Freedom’s Reach, which bears a number of striking similarities to Earth-Prime’s Freedom City.

MOUNT ATLAS

The volcanic Mount Atlas near Emerald City features ancient lava tunnels and underground passages connecting to Sub-Terra. Some of the cryptids in the Elysium Forest near Mount Atlas may have originated in or traveled through Sub-Terra to get there.

PRIMORDIA

Sub-Terran tunnels connect to a massive cavern complex surrounding a single, vaulted cave several miles in length. Dubbed “Primordia” by the Atom Family, this cavern may have been mistaken for the “hollow world” or other versions of the “inner-earth” in myth and legend. It contains a miniature biosphere very much like prehistoric Earth, complete with a tropical jungle covering the floor of the main cavern, populated by dinosaurs and other primeval creatures, and small scattered tribes of primitives, including humans. An artificial “sun” hovers near the center of the peak of the main cavern, ensuring it is always daylight in Primordia.
Dr. Atom speculates that Primordia was the creation of either the ancient Serpent People or, more likely, the alien Preservers, perhaps as a precursor to their creation of The Lost World and Farside City.

PYROS

Pyros is a city of basalt buildings and towers carved and shaped out of volcanic rock by the Magmin, surrounding a central cavern where a lake of molten rock bubbles like an infernal cauldron, rivulets of magma flowing past some of the high towers, into deep ravines and out elsewhere into Sub-Terra.
Pyros is a strange imitation of surface world life, with the lumbering Magmin slowly building and re-building the city to maintain it against the force of occasional tremors and magma bursts. They neither need nor cultivate fields or livestock. They take rest in some of the buildings, and use others for strange rituals—apparently of worship or meditation (or both). Otherwise, it is a largely silent pantomime with no apparent point to it: The Magmin have none of the needs of surface creatures and do not even reproduce. Some speculate their actions are simple lingering programming or conditioning from the creation of their ancestors by the Serpent People, or there could be some larger purpose known only to the Magmin.
Whatever its purpose, Pyros is rarely seen by outsiders, unless they are brought there as prisoners of the Magmin. The inhabitants vigorously defend Pyros from intruders. Given the dangers of the terrain, most of the inhabitants of Sub-Terra are content to leave the Magmin city alone. It is of little use to anyone else, and the Magmin there are not usually aggressive unless provoked.

Geography

How can an underground realm like Sub-Terra even exist? Thousands of miles of tunnels riddling the Earth’s crust? Entire vast caverns containing ancient, ruined cities? Rivers of magma flowing through the basalt fortresses of the Magmin—the whole of it seems not only too fantastic, but scientifically impossible. If the Earth’s crust were truly as shot-through with tunnels and caverns as Sub-Terra suggests that it is, it would be as delicate as lace, unable to withstand the pressures of the planet’s core. That is saying nothing of the apparent disconnect between distances and environmental conditions found in Sub-Terra, where creatures sometimes appear to travel thousands of miles in a fairly brief time underneath the surface of the Earth.
Dr. Atom has speculated some, if not most, of the Sub-Terran tunnels and caverns run through dimensional “faults” like the passages to the Lost World and similar “hidden places” on Earth. Indeed, there is at least one known passageway to the Lost World from Sub-Terra, and vice versa, and other tunnels there could lead to other worlds, places, or even times.
More mystically-minded scholars have pointed out that Sub-Terra’s major tunnels and passages tend to follow the contours of Earth’s network of ley lines, flows of magical energy through the “body” and “aura” of the planet, representing dimensional forces ebbing and flowing much like the movement of the continents themselves, forming “fault lines” and places of dimensional stress and weakness. This lends credence to the theory that much of Sub-Terra is not actually “inside” the Earth, but in an interstitial interdimensional realm of its own, strongly linked to certain caverns and geological features on Earth. The deeper one goes into Sub-Terra, the stranger and less connected to Earth’s reality it seems to become.
Parts of Sub-Terra appear to shift, seemingly at random, or in response to events on the surface world, or changes in the flows of dimensional energy. Among other things, this often means visitors never see quite the same SubTerran terrain twice; tunnels appear to move, maps never remain useful for long, and new and unusual places spring up seemingly out of nowhere. These changes don’t seem to happen while anyone is observing them, and Dr. Atom speculates that intelligent creatures may “stabilize” parts of Sub-Terra through their presence in a kind of “macro-observer-effect.” Nevertheless, the apparent shifting of the Sub-Terran terrain can be disorienting, causing visitors to become lost and trapped, unable to find their way back to the passage linking them to the surface world.

Type

Underground / Subterranean