What Caused the Eruption of the World's Largest Mud Volcano?

On May 29, 2006, a torrent of mud spewed from vents that opened up in the ground in a densely populated area of the Indonesian island of Java. That mudflow eventually buried houses, businesses and roads over an area twice the size of Central Park in New York and drove tens of thousands of people from their homes. More than 11 years later, mud, rocks and gases still sputter from the gashes in the earth there.