A 7.9 magnitude earthquake rocked most of China on Monday killing several thousand people. At this point it is believed that nearly 10,000 have been killed by an earthquake that was the strongest seen in several decades. At one school, almost 900 students -- all eighth-graders and ninth-graders, were believed to be buried by rubble. On Monday night at least 50 bodies were pulled from the rubble at another school. Meanwhile, 2,300 people were buried in two collapsed chemical plants in Sichuan's Shifang city while 80 tons of ammonia leaked out. Six hundred people died there. The plants were among a series of buildings that collapsed, including private homes, schools and factories as the earthquake continued. The last major earthquake in the region occurred in the epicenter area when a 7.5-magnitude quake killed more than 9,300 people on August 25, 1933.