A 7.5-magnitude earthquake rocked northeastern China, near the coast, on July 28, 1976. Centered in Tangshan, the main quake and a major aftershock 15 hours later killed at least 240,000 people, according to official estimates – but some sources say as many as 655,000 may have been killed. Yet by either account, according to the US Geological Survey, this was the deadliest earthquake in four centuries and the second deadliest on record. Almost 800,000 additional people were injured.