In Greek mythology, Delphi was the site of the Delphic oracle, the most important oracle in the classical Greek world, and a major site for the worship of the god Apollo. Apollo's sacred precinct in Delphi was a panhellenic sanctuary, where every four years, starting in 776 BC athletes from all over the Greek world competed in the Pythian Games, one of the four panhellenic games, precursors of the Modern Olympics. Delfoi in an UNESCO world heritage site.