Sunday marks the first anniversary of the earthquake and subsequent tsunami that struck Japan last year, leading to one of the worst nuclear crises in history.

As vigils and ceremonies take place to mark the occasion, the nation continues to work to recover from that triple disaster.

Japanese Prime Minister Yoshihiko Noda wrote in the Washington Post Saturday that Japan will forget neither the nearly 20,000 people lost in the disaster nor the outpouring of support from other nations after the event. He said Japan is “deeply indebted” and “forever appreciative.”

At a formal ceremony in Tokyo and elsewhere on Sunday, much of Japan's public routine will stop at 2:46 pm local time to mark the moment last March 11 the 9.0 magnitude earthquake struck off Japan's east coast. The temblor sent an enormous wall of water crashing into seaside towns and villages.

The wave struck the Fukushima Dai-ichi nuclear power plant, causing three reactors to melt down and leaving some tracts of land uninhabitable for decades because of radiation levels. A year later, people are still living in temporary shelters, many of them still unemployed as they struggle to put their lives back together.

Much of Japan's worst-hit areas are now clear of debris, but the extent of the damage is such that it may take many years before some regions can start rebuilding.