• Entry
  • Reader's guide
  • Entries A-Z
  • Subject index

The Mayan calendar, which originated as early as the 6th century BCE, was based in part on the traditions of earlier Central American cultures, including that of the Olmecs. The Mayans made careful observations of the moon, sun, and stars. From ...

    • Loading...
    locked icon

    Sign in to access this content

    Get a 30 day FREE TRIAL

    • Watch videos from a variety of sources bringing classroom topics to life
    • Read modern, diverse business cases
    • Explore hundreds of books and reference titles