Twenty-five years ago next month, tens of thousands of people in the northwestern corner of the Soviet Union fled after watching plumes of radioactive smoke rise from the explosion of the huge Chernobyl nuclear plant.
A quarter century later, they still have not returned. The "exclusion zone," a 30-kilometre circle of land, formerly home to 200,000 people, surrounding the reactor town of Pripyat, now in Ukraine near the border of Belarus, remains empty and uninhabitable.
A Soviet high-tech town whose 50,000 inhabitants lived in neat apartment blocks peppered with utopian sculptures, Pripyat now sits deserted, cars still parked on the streets. Inside the child-care facility, toys and dolls remain scattered and fading where tiny children, now well into their adult lives, dropped them when they were ordered to leave.
The town is surrounded by forests which, according to some studies, now teem with wildlife because so few humans have dared enter them.
Radiation levels around the plant remain so high that authorities do not expect the area to be inhabitable for between 180 and 320 years.
It is hard to know how many people were killed or sickened by the Chernobyl disaster. More than 300,000 were moved, many not until weeks after the radiation was known to be lethal. Most of the fallout landed in what is now Belarus, a secretive and difficult authoritarian state. Aside from the 57 people immediately killed, studies have suggested that anywhere from 2,000 to hundreds of thousands of people may have contracted cancer and other radiation-related diseases. Birth defects are measurably higher in the areas of Belarus and Ukraine near Chernobyl.
Today, the largely decommissioned Chernobyl plant still has 3,800 full-time employees, although none of its reactors has operated since 1999. Several thousand more Ukrainians are employed to guard the exclusion zone - because of the radiation, they work two-week shifts followed by two-week decontamination periods.
The plant itself remains a hazard: The hastily-built cement containment sarcophagus, assembled amid deadly radiation by suicide squads of liquidators in 1986, is crumbling, partly exposed to the elements.
A permanent steel and concrete container, designed to last a century, was supposed to be finished five years after the disaster. Mainly because of corruption and factional struggles within Kiev's fractious governments, the project has gone decades behind schedule and hugely over budget; after spending $750-million (at least $71-million of which came from the Canadian government).
Nothing has been finished and it is unlikely to be done by its 2012 completion date. Scientists worry that further delays could expose highly radioactive dust to the environment, risking the poisoning of more people and a second Chernobyl disaster.