Which Mayan structure was notable for improving calendar accuracy?

The Caracol in Chichen Itza is notable for its role in improving the accuracy of the Mayan calendar due to its unique architectural design and astronomical functions. This structure features a circular tower that was used by Mayan astronomers to observe celestial bodies, allowing them to track the movements of stars and planets more precisely. The observations aided the Maya in creating a more accurate calendar system, particularly for agricultural and ceremonial purposes, which were crucial for their society.

The Caracol's alignment and features demonstrate the sophistication of Mayan understanding of astronomy. While other significant structures like the Pyramid of Kukulcan and the Temple of the Inscriptions served various ceremonial or political purposes, it is the Caracol that specifically highlights advancements in the measurement of time and celestial cycles. The Great Ball Court, on the other hand, primarily served as a venue for the Mesoamerican ballgame, lacking a direct correlation to calendar improvements.