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 who battled and killed the Python, a dragon who lived there and protected the site. In ancient times pilgrims came from all over the Greek world to seek advice from the god Apollo, via his oracle, at the beautifully situated site on the slopes of Mount Parnassus, known as Delphi. The site was also the venue for the Pythian Games, a sporting tournament held every four years (beginning in 776 BC) which attracted famous athletes from all over the ancient Greek world. The Pythian Games were one of the four panhellenic games which are considered precursors of the modern Olympics. Today tourists flock constantly in the wake of the pilgrims of old up the Sacred Way to marvel at the remains of the marble Sanctuary of Apollo, the Castalian Spring and the Sanctuary of Athena. There is an excellent museum at the site, which is northwest of Athens in the prefecture of Fokida. Delphi is scenically spectacular and the views and photographic opportunities are enviable. The site is extensive and it is ideal to stay overnight to explore thoroughly.