On December 26, 2004, a 9.0 earthquake hit Sumatra and estimates say that over 110,000 people have been killed. Though the earthquake was powerful (it's tied for fourth largest since 1900) and the devastation is immense, it is not the deadliest earthquake. In 1976, a 7.8 earthquake hit the city of Tangshan in China and killed approximately 240,000 people. Learn more about the deadliest earthquake of the 20th century.