Japan is marking the first anniversary of the earthquake and tsunami which devastated the north-eastern coast on March 11, 2011.
The 9.0 magnitude earthquake hit at 2.46pm local time and, soon after, an immense surge of water swept away entire communities along the coast.
The quake triggered a serious nuclear accident at the Fukushima Daiichi nuclear plant, and thousands of people were evacuated as a result.
Both disasters claimed more than 15,800 lives and more than 3,000 people are still unaccounted for.
BBC News reports that the main memorial ceremony was held at Tokyo's National Theatre. It was attended by Japan's Emperor Akihito and Prime Minister Yoshihiko Noda.
Memorial services took place all over Japan and a minute's silence was observed at 2.46pm, the moment the quake hit.
In the north-east, warning sirens sounded at the precise time of the quake, and bells and prayers were heard across the country.
One day before the national memorial services, the families of victims began to visit graves and, in Iwaki City in Fukushima, thousands of candles were lit, bells were rung and monks chanted.
Click on the image below to see our gallery of 'tsunami' clouds...