The ancient Mayan civilization is known for developing a calendar system based on astronomical observations. The Mayans constructed an intricate and sophisticated calendar comprised of multiple interlocking cycles, such as the Tzolk'in (a 260-day ritual calendar) and the Haab' (a 365-day solar calendar). Their deep understanding of astronomical cycles allowed them to track celestial events, predict eclipses, and structure agricultural activities according to seasonal shifts. The Mayan calendar not only served practical purposes in daily life but also played a significant role in their religious and ceremonial practices, illustrating their advanced knowledge of astronomy and timekeeping.