Which two cultures are best known for its development of calendars?

The ancient Egyptians and the Maya are two cultures best known for their development of calendars. The Egyptians created a solar calendar with 365 days, which was instrumental in agricultural planning and religious activities. The Maya developed a complex calendar system that included both a 260-day ritual calendar and a 365-day solar calendar, showcasing their advanced understanding of astronomy. Both civilizations used their calendars for religious, agricultural, and administrative purposes.