In 2010 a large object detonated on entry into Earth's atmosphere, no one knows what it was. Theories range from alien spacecraft through acts of God or simply a comet containing materials and substances so far unknown to humanity.
Rather than simply being vaporized, fragments of the object were tracked as they made rapid descent, trailing flames and smoke, to various parts of the planet. The five primary impact sites were Chernobyl, New York, a location in Eastern Russia known as Dyatlev Pass, an impact site in the Mediterranean(The Ghost Sea) and an impact site in Portugal near the coast of the Atlantic Ocean.
At first it was thought that the fragments were simply radioactive, as there were mass reports of illness and inexplicable injuries ranging from internal haemorraghing through burns and electrocution by people near the impact sites. Before an actual study could be undertaken of the fragments, however, each site began manifesting what's been simply known as Anomalies since then. Bizarre irregularities in reality which remain stationary, but react violently to contact with organic life or fast-moving objects, ranging from radiation pulses through cerebral bleeding/bruising and discharges of electricity that would put thunderbolts to shame. Some have also been known to do odd, gravity-related things to the objects or creatures that trigger them.
The Zones within which Anomalies manifested began to spread even as the evacuation efforts were underway, but eventually settled in roughly cylindrical zones of influence(circular on the ground, but extending to the edge of the atmosphere upwards) that occasionally bulged, occasionally settled with no perceptible rhyme or reason. Those smaller fragments which were not shattered on impact manifested such Zones as well, though much smaller. The two most well-known Zones are the Chernobyl Zone and the Greater New York Zone(the fragment impacted on Manhattan and its radius was large enough that most of New York's suburbs were included in the sealed-off area).
Zone Lifeforms
While humans have no reliable way of detecting Anomalies except hucking small objects ahead of them as they go, or using geiger counters or watching for the Anomalies that produce visual disturbances, most animals seem to have a sixth sense that permits them to dodge anomalies with ease(though if panicked or frenzied they might still enter into one). Resultingly, the Zones are often rife with animal life, and free from human interference plants tend to grow freely as well, their vines and boughs curving to avoid even small Anomalies.
However, the Zone is not entirely benign, while plants are mostly unaffected, many animals that make their homes within the Zones have begun manifesting mutations ranging from abnormal size through small-scale psychic abilities and increased intelligence. There are also reports that humans are sometimes affected, but these are unconfirmed.
The Chernobyl Zone
The local governments soon realized that keeping treasure hunters, scientists and bandits out of the Chernobyl Zone was a hopeless task. Instead they decided to simply tax these people on whatever they dragged out, as well as confiscating anything particularly dangerous. Today the Chernobyl Zone's border is a bustling city all of its own, brimming with booths selling prospective explorers(dubbed Stalkers) everything from novelty headgear to firearms and explosives. The Chernobyl Stalkers are unofficially competing to see who can reach the Zone's heart first, as rumour has it that there are true wonders there. Everything from a device that can grant wishes to the technology of dead aliens has been theorized.
Getting to the heart of a Zone is not as easy as it sounds, however, Anomalies increase in size, frequency AND bizarreness the closer a person is to the heart of a Zone. The local lifeforms also tend to be more aggressive.
The Greater New York Zone
America's government went the opposite route, sealing off the New York Zone on land with a massive barrier incorporating concrete slabs, barbed wire and electrified fences. This did not stop the Stalkers already inside, nor those citizens who had refused to evacuate. To make matters worse, as soon as the first rumours of "artifacts" began to come out of the Chernobyl Zone, American "entrepreneurs" worked around the clock to find ways of circumventing the New York Barrier. Everything from tunnels through ultralight aircraft and pretending to be scientists. Nonetheless, the New York Zone is much less heavily populated, at least by humans, than the Chernobyl Zone.
The US Military launches occasional scientific expeditions, however, and makes an effort to map out the sea-based anomalies in an attempt to find a safe route to Manhattan by ship. Easier said than done, however, as ships and planes cannot as easily stop if they suddenly spot an Anomaly in the water or air, making air and sea travel near the Zones essentially null.
The Artifacts
Artifacts, the one thing that makes visiting the Zones such a tempting prospect. Most Artifacts are reminiscent of crystals or rocks with unusual shapes and a glow to them, incredibly pretty on their own and likely worth selling just for that, but the true powers of the Artifacts become visible when they're in direct contact with human(or potentially animal, though no one has checked) skin. Most traditional Artifacts provide a constant low dose of radiation to the wearer, in exchange for which he receives just about anything from minor clairvoyance through resistance to many of the Zone's anomalies. Not all Artifacts are radioactive, though, some have physiological effects instead, like thinning the blood or slowing the wearer's reflexes.
Most have a beneficial side effect to go with whatever havoc they wreak on the wearer.
Additional Reading
Twister, an anomaly.
