Following the 1986 nuclear accident, a 30km zone around the Chernobyl nuclear power plant was evacuated. The abandoned area, contaminated with radioactive dust, is now an overgrown wilderness. BBC Nature had exclusive access to the zone with a team of scientists studying the effects of radiation on wildlife there.
Animals, particularly birds, have made use of the zone's empty buildings. Many ecologists say that the absence of man has gradually led to an increase in the biodiversity there. But one team of researchers say they have seen evidence of the underlying effects of contamination.
The team carrries out a lot of its wildlife surveys in the Red Forest, some small patches of which are highly contaminated. Geir Rudolfsen from the Norwegian Radiation Protection Authority comes here to study bird fertility. He says the zone's forests are strangely quiet.
The team works in some areas that are less than a kilometre from the infamous power plant. The zone is a patchwork of relatively clean and very contaminated areas, and the researchers say there are fewer animals in the "dirtier" parts of the zone.
While the majority of the team sets up nets to catch birds, some members, including Zbyszek Boratynski from the University of Jyvaskyla in Finland, head out into the zone to set humane traps for small mammals. Dr Boratynski takes a reading to measure the radiation in every location he sets a trap.
In their temporary field camp, Tim Mousseau and Anders Moller, the researchers leading the expedition, log each bird they catch in the mist nets. They measure, weigh and take blood samples from every animal.
While travelling around, the team catches a glimpse of a herd of wild Przewalski's horses that were released into the exclusion zone in 1998. The hope was that the Critically Endangered horses would thrive in this human-free landscape. They are breeding, but scientists in Ukraine say they are now under threat from poaching.
In Kopachi, one of the closest villages to the nuclear plant, an abandoned kindergarten is the only building that still stands. It contains toys, drawings and books left behind when the children fled.
Pripyat was the largest town in what is now the exclusion zone. More than 50,000 left their homes for good after the accident. Today, it is difficult to tell where the town ends and the countryside surrounding it begins.
Pripyat's famous Ferris wheel was never used. The town's fairground was just days from opening when the accident happened. Today, tourists - most of them wearing dust masks to avoid breathing in contaminated dust - visit what is now a ghost town.