Time: Dec, 1986
Place: Chernobyl, Ukraine, U.S.S.R
Details: in December 1986, with the help of a remote camera, they discovered an intensely radioactive mass more than two meters wide in the basement of Unit Four, which they called "the elephant's foot" for its wrinkled appearance The mass was composed of melted sand, concrete, and a large amount of nuclear fuel that had escaped from the reactor. The concrete beneath the reactor was steaming hot and was breached by now-solidified lava and spectacular unknown crystalline forms termed Chernobyl site. It was concluded that there was no further risk of explosion.