This month marks the 12th anniversary of the Fukushima disaster, when three nuclear reactors in Japan suffered catastrophic meltdowns.

A tsunami knocked out the reactors’ cooling systems. The plant was shut down, but radioactivity sent temperatures soaring past the melting point of steel.

Radioactive gases mingled with superheated steam and explosive hydrogen gas, which detonated, spreading radioactive contamination over a vast area; 120,000 people were evacuated and 30,000 are still unable to go home.