Like other Mesoamerican peoples, the traditional Mayas recognize in their staple crop, maize, a vital force with which they strongly identify. This is clearly shown by their mythological traditions. According to the 16th-century Popol Vuh, the Hero Twins have maize plants for alter egos and man himself is created from maize. The discovery and opening of the Maize Mountain - the place where the corn seeds are hidden - is still one of the most popular of Mayan tales. In the Classic period (200-900 AD), the maize deity shows aspects of a culture hero.