When did the Fukushima nuclear disaster happen?

A magnitude 9.0–9.1 earthquake off Japan's northeast coast triggered a tsunami with waves over 14 metres high at the Fukushima Daiichi plant. The flooding knocked out backup power and cooling systems, leading to meltdowns in three reactors and hydrogen explosions. It was rated level 7 on the International Nuclear Event Scale, the same as Chernobyl, the highest level. More than 150,000 people were evacuated from the surrounding area. The earthquake and tsunami themselves killed around 18,000 people, while the nuclear accident's cleanup is expected to take decades.