The world's worst nuclear accident occurred 26 years ago -- on April 26, 1986 -- at Chernobyl's reactor No. 4. The unprecedented inadvertent release of radiation was compounded by inaction: The Soviet Union didn't disclose the accident until after the radiation cloud was detected in Sweden, and even then failed to warn of the scale of the disaster. In that time, residents of Ukraine, Belarus and beyond went about their lives, ignorant of the radioactive dust descending upon them.
Award-winning American photographer Joseph Sywenkyj over the years traveled several times on assignment to the Chernobyl 30-kilometer (about 19 miles in radius) exclusion zone, creating these images.
Left, the entrance to the exclusion zone in Ukraine.