In the early 25th century the earth is a radioactive ruin, fallout from a World War fought over who would be allowed to respond to a message from an interdimensional probe of alien origin. Now humanity scavenges off what is left, seeking to exploit knowledge and potential over a lack of infrastructure and population. What ruins remain are populated. One of the greatest is a sunken city in the Strait of Gibraltar known as Roma Lux Aeterna. It is humanity's greatest hope of civilization. But of course there are other ruins. In the east lies the Imperia of the Child Empress, over North America flies Skybin, and many intrepid explorers have built communities among other ruins.
Aeterna - This city is a grid of tower tops. Most of them have been flattened to form courts where the elite of Eternia rule their territories. Thrones and synthetic plants are common, as are nose piercings that dampen the sense of smell. For the waters around Eternia are filth, a mix of unprocessed sewerage and toxic waste. Those who can afford it live in the towers themselves, those who cannot live in a system of piers that choke the waterways. The underwater levels of the towers are flooded, unused, and uninhabited. Without the manpower to repair them the city must rely on the engineering of the city to keep afloat. Several nearby islands in the area have been claimed as Plazas, including the Tager Research Facility on Gibraltar Plaza.
Imperia - The Imperia of the Child Empress is a land of rampant biotechnology and consumerism, without the high technology and learning of Aeterna. The waters of the eastern sea are more sterile than polluted, and bioengineered kelp beds feed the coastal and island communities of the east. The Russian Sea Wall, which isolates the South China Sea, originally was intended to keep submarines out but now keeps currents from flowing in. The Child Empress herself is still only ten, but is using biotechnology to preserve her youth and vowing only to grow older when it is time to marry for political purposes. But as Aeterna remains fractured, and Skybin isolationist, it is unlikely for her to marry. Imperia troops are not clones but instead augmented to be the peak in human capability. Upon leaving the army, these restricted combat are replaced for civilian ones at no cost. Thus those who want to be modified, often spend a stint in the military first.
Skybin - Using dimensional shunt technology, a group of Objectivists sought to escape the war. They succeeded, removing a triangular section of land to Phase Space. When they returned, their city was stuck in a gravity-defying orbit 2.6 miles above sea level. Currently it rests over what was once Indiana. Its original location, including part of Missouri, now suffers from a giant hole, similar in appearance to the Grand Canyon. Skybin's population reverted to farming when their technology proved insufficient for the job, although a certain elite remains. These elite live in a large central tower from which they oversee the population. A force of high technology warriors called Dragoons serve as defense and a raiding force to steal technology from other sectors. Skybin is naturally lacking in raw materials. Most power is solar powered, and large UV collectors take advantage of the thinner atmosphere. Most of the population has a heavy tan from the same source, identifying them easier to those tower dwellers who live in the shade of large UV filters.
Population: The world population is estimated at 400 million. Birth rate and death rate is about even, but the number of mutants is rising steadily. Although genetic modification currently allows advanced fertility treatments, the infrastructure doesn't exist for it to be provided to everyone. Less than 10% of people have access to it. Most ethnic groups survive, but many cultures have been lost.
Fashion: Generally people prefer to wear synthetic, non-absorbent materials like vinyl or flexible metal. This is because the atmosphere is so bad, it can cause serious medical problems if kept in contact with the body. In bad weather, everyone wears masks. Hygiene is important, but technology makes it easy to look after yourself. Bright colors are common, but people normally keep to human norms besides hair and eye color. Tattoos and body paint are uncommon among the elite because they are so commonly used by the lower classes to cover up disfiguring sores. As most of the population is in the tropical latitudes, revealing clothing is also popular, especially as the available clothing options don't breathe.
Technology: Is normally high, but scavenged and unreliable. Most notably, the technology that does exist was made for much less hostile environments. Sure, you may have a fusion generator that powers everything, but it can't handle the high levels of radioactive dust in the atmosphere, and neither can your wrist computer. The world as it was certainly wouldn't have problems modifying their technology... but people now do. While its easy to replicate, it's hard to innovate, and the support systems for scientific progress on any scale don't exist. Most people are ignorant of basic science. Space travel is possible, but nobody has the resources to spend on that, and in fact a sizable portion of humans are descended from space colonists who returned to Earth when support lines dried up. What is available: Cheap unlimited energy sources. High-tech alloys scavenged from ruins and melted down into new forms, and plentiful supplies of most other material. Hard light and advanced cybernetics. Biotech, but limited to human and agriculture: Traits can be copied, and a few new genes exist, but the ability to generate new or mixed species exists only as prototypes. Advanced weapons technology exists, but most of it is experimental: it only got to see one war, and nobody learned from it, just died. The infrastructure for Cloning doesn't exist, but its theoretically possible. Medical technology is good, but few doctors exist. Sure, herbal medicine can heal the common cold, but not when it's aggravated by many exotic kinds of poisoning, and any bacteria . Any kind of unreproducible or labor expensive to reproduce high technology is kept in 'clean room' status to avoid quick degeneration. Most kinds of high technology discoveries are in the form of automated infrastructure. Few of these were kept in clean-room conditions, so a clean room must be constructed around them before the can be used.
Environment: Toxins are in every water source on earth. Rain is bad enough, dragging down lingering pollution, acids, and nerve gas. It can be bad for your health, but on the continent it is likely to produce flash floods. In this form, contact is deadly. The poisonous dust of the earth turns rain runoff into a corrosive slime that anyone who is rescued from, is likely to still die. Surprisingly, most plant life exists in highly radioactive regions that encourage mutation, so seeing a bed of clover is actually a bad sign. These mutated plants are almost universally bad to eat, but they do not spread the radioactive material, instead trapping it in the soil where it stays until washed away by the rain. Animal life is almost nonexistent, even in the oceans. The exception is a few strains of giant cat kept carefully alive by the wealthy. Impractical, but it's a status symbol and a sign of hope. Breeding programs often span the world. What this comes down to is, people don't eat the food; they don't drink the water. Most people subsist on reprocessed food and water. Technology exists so that it is pretty good, but mere distillation of water isn't enough, so it has to be transported from larger facilities.
Transportation: Although roughly 20% of the population live in large cities, 80% of the population exists outside of it, and don't have the facilities needed to support life. Thus a transportation network is required. Most transports were made pretty reliable before the War; it's simply less efficient if you have to pay for maintenance. But that also means that most transports are HIGHLY efficient, they can't go any faster. Thus a slow, stable network exists. Most of it is ocean-based, as they were made to be water tight and so avoid most of the issues, besides corrosion. But inland, rivers are worse than ground, so large wheeled vehicles travel the ridge lines between settlements. The plains are, after all, death traps when it rains. So tracked vehicles are unacceptable in most places. Surprisingly, VTOL engines were designed that require little maintenance, even in the highly corrosive air. Essentially ramrockets, these aerial transport devices allow the easy transportation of heavy equipment and personnel from place to place, meaning that more efficient land travel is mostly relegated to the necessities. VTOL craft also have another advantage in that they are rarely pirated. Bandits are incredibly common, as communities off the grid still are largely incapable of supporting themselves. Most vehicles are armed and armored, but so are the bandits. Some highly advanced technology allows VTOL craft to be captured without destroying the ship. These are mostly in the hands of the military, but some bandits have captured one of the numerous pre-war military installations. Magnetic grapples, highly accurate missiles, and energy-draining ray guns all can force a plane to make an emergency landing in range of the bandits to capture them.
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