On 11 March 2011 a magnitude 9.0 earthquake off north-eastern Japan triggered a tsunami that overran coastal defences and killed close to twenty thousand people. The waves also disabled cooling at the Fukushima Daiichi nuclear plant, causing meltdowns and the long-term evacuation of a wide exclusion zone. Reconstruction raised sea walls, relocated some communities to higher ground and rebuilt others in place. The nuclear disaster prompted many countries to reconsider atomic energy.
It tested the limits of coastal engineering and nuclear siting, and its relocation and sea-wall programmes became a major laboratory for disaster-driven planning.