Sixteen years ago today, a nuclear reactor in Chernobyl exploded, resulting in the worst atomic accident in the history of the world. The explosion affected 3.3 million Ukrainians as well as untold numbers of other people, and sent a radioactive cloud drifting over much of Europe. All of the area within 18 miles of the plant has been a no-man’s-land since the accident, but last year, under urging from the U.N. to focus on redevelopment, the Ukrainian government began contemplating building in the area. That move provoked an outcry from victims groups, who point to ongoing ill effects from the explosion. The number of thyroid cancer cases, for example, has risen from 119 in 1986 (prior to the explosion) to 3,022 last year.