The ancient civilization known for its elaborate pyramids and complex calendar is the Maya civilization. Flourishing in Mesoamerica, particularly in present-day Mexico, Guatemala, Belize, and Honduras, the Maya achieved remarkable advancements in various fields, including architecture, astronomy, and mathematics. Their pyramid structures, such as those found in Tikal and Chichen Itza, serve as iconic symbols of their architectural ingenuity. Additionally, the Maya developed a sophisticated calendar system based on astronomical observations, which reflected their deep understanding of celestial cycles and timekeeping, further underscoring their cultural and scientific legacy.