On April 26, 1986 — 40 years ago today — a reactor at a Soviet nuclear power station 80 miles from Kiev — now Kyiv, Ukraine — exploded. Much of the radioactive core was vaporized, thrown into the ...

Photographs from the first days of the Chernobyl disaster and of the aftermath years later show the response, the evacuation and the long-term consequences of the world’s worst nuclear accident. In ...