On December 26, 2004, a gigantic earthquake ripped apart the floor of the Indian Ocean off the coast of Sumatra. The force of the quake, transmitted upward to the surface, sent a tsunami, or a series of giant waves, in all directions toward unprotected shores and unwarned populations, many in remote areas or secluded vacation spots. Within 12 hours, more than 200,000 people had been killed, and many more were left injured or homeless, their livelihoods destroyed. Cities and villages lay in ruins. Even the geography of the Earth was changed. But as the affected countries, with help from around the world, struggled to recover, scientists warned that the next deadly tsunami could come at any time. The question remains whether the world will be any more prepared for the next one.