The Castalian Spring, at the foot of the Phaedriades cliffs just outside the main sanctuary, was where ancient visitors to Delphi ritually purified themselves before consulting the oracle. According to myth, the spring was named for a nymph who threw herself into it to escape Apollo. Two fountain houses were built here over the centuries to channel the spring’s water: an Archaic-period basin and a later Hellenistic/Roman one, whose remains can still be seen on site today. The nearby “Python’s Den” refers to the cave associated with the serpent Python, said to have guarded the site before being slain by Apollo. [Editor’s note: the original site had only brief photo labels for this page. This paragraph was drafted as a placeholder and should be reviewed/expanded by Dr. Siegel.]