Japan is observing the sixth anniversary of the powerful earthquake and ensuing tsunami that caused the country's worst nuclear accident in 2011.
The twin natural disasters in the country's northeast left some 18,500 people dead or missing. About 123,000 people who were evacuated still have not returned home, and many of those evacuees are still squeezed into prefabricated temporary housing.
Memorial services will be held across the country and a moment of silence will be observed at 2.46pm local time, the exact moment the magnitude-9 quake hit the country six years ago.
After the tsunami swept through later that day, the Fukushima Daiichi power plant suffered meltdowns at three of its six nuclear reactors, spewing radioactive materials into the environment.
The emergency prompted hundreds of thousands of residents to flee the region, as operator Tokyo Electric Power struggled to bring the nuclear plant under control.
The triple meltdown at Fukushima remains the world's worst nuclear disaster since the Chernobyl accident in the Soviet-controlled Ukraine in 1986.
It will take at least four decades to decommission the Fukushima plant, the operator has said.
March 27, 2011: A man walks through the destroyed neighbourhood below Weather Hill in Natori, Japan. Source: AAP