Epidavros was a healing center that flourished in the Peloponnese for 1,000 years, beginning in the 5th century B.C. In ancient times, it was known for its cult, dedicated to the Healing God, Asklepios (note the staff and serpent, the symbol for health organizations, even in modern day).
Today, however, Epidavros is known primarily for its 14,000 seat Theater, buried in ancient times and not uncovered until the 1800s.
“Patients” would come to Epidavros from all over to be treated by the priests of the cult of Asklepios. They would stay here for extended periods, praying at the temple:
And they would be treated by the priests, who used some advanced surgical implements found at the site.
But, mostly, the therapy that patients received was that they were made to sleep in this building while the priests allowed non-venomous snakes to slither amongst them and in the dreams (nightmares?) that would come to the patients while they slept, their treatment would be unveiled:
Uh, huh. I think they just had the bejesus scared out of them so much that the ones that were faking their illnesses were miraculously cured.