Japanese Prime Minister Naoto Kan has thanked people around the world for their response to the earthquake and tsunami. Signed newspaper advertisements said the support had brought hope and inspired courage at a desperate time. Ceremonies and a one-minute silence were held to mark the moment of the unprecedented disaster, triggered by a 9.0-magnitude earthquake exactly a month ago. It is estimated to have killed 28,000 people and left one lakh fifty thousand people homeless. Some villages on the north-east coast of the main Japanese island of Honshu were largely destroyed. The disaster also severely damaged a nuclear plant, which is still causing severe problems for the authorities.