Mayan contributions were many. They developed an advanced writing system. Their history, entrusted to cactus fiber parchment, fared poorly against the ravages of time and Spanish censors saw to the destruction of much of the remainder. However, many of their carvings on stone have survived and provide much of what is known today about their civilization. The Mayans also were gifted mathematicians who independently developed the concept of zero, and astronomers who deduced that a solar year was slightly more than 365 days. Despite these achievements, the Mayans and other Meso-American cultures failed to discover the utility of the wheel.
The decline of Mayan civilization was well under way by 1100 B.C. The causes are uncertain, but speculation points to warfare, crop failures and disease as leading possibilities. By the time of the Spanish arrival around 1520, the Mayans were a starkly diminished civilization; their great cities were abandoned and the remnants of their population widely scattered.
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