The park is open 5am to 10pm.
The main purpose of the Amphitheater was to provide entertainment, and also allow people to watch shows, plays, and performances outside. The Amphitheater was put I side of this specific area because the surrounding valleys echoed the sound to the "seats", making for a convenient viewing experience.
While mostly reverted back to nature, you can plainly see the terraces where people once sat.
Please make sure the cache is tucked away securely as this is a high traffic area.