The most radioactive places on earth

Nuclear energy is clean and efficient when everything works. The U.S. powers aircraft carriers, submarines, and even cities with it, but there are obvious down sides: Disasters can lead to death, destruction, and poisonous radiation.

Nuclear accidents are graded from zero to seven, zero being no safety issues and seven being extremely hazardous to health and the environment. Two examples of major nuclear incidents include the 1986 disaster in Chernobyl, Ukraine and Fukushima, Japan in 2011.

Although no occurrence of this magnitude has happened in the United States, the Department of Energy has been tasked with cleaning up over 100 nuclear sites within its borders, according to this TestTube video.