Chernobyl
The Chernobyl disaster began as a safety test
On 26 April 1986 engineers ran a late-night test to see if a dying turbine could power the cooling pumps. The test pushed Reactor 4 into an unstable state and it exploded within seconds.
More in Chernobyl
The exclusion zone became a wildlife sanctuary
With humans gone, the 2,600 km² zone filled with wolves, lynx, bison and wild horses. Radiation still lingers, but for most species the absence of people has been the bigger factor.
Reactor 4 sits under the largest moving structure ever built
The New Safe Confinement arch is 108 m tall and weighs 36,000 tonnes. It was assembled beside the reactor and slid into place over it — the biggest object ever moved on land.