Monday marks the one year anniversary of the tsunami that devastated the Indian Ocean coastline from Malaysia to East Africa and memorials to the victims of that natural disaster have already begun.

In Thailand Saturday, some mourners prayed, others observed a moment of silence while separately the country's sea gypsy tribe, the Moken, banged drums, chanted and made offerings to the sea.

The tsunami, triggered by a massive earthquake off Sumatra island, killed more than 200,000 people and left more than two million people homeless.

Many ceremonies are planned for Monday, when survivors, relatives of victims, government officials and others in the region and around the world mark the day that one of the worst natural disasters in recent history occurred.