Sybil's Cave is a cave with a natural water spring, that is now buried at the bottom of the Stevens Institute of Technology hill, near the Castle Point Skate Park on Frank Sinatra Drive. One of Hoboken's best known landmarks, it was first excavated around 1832 by Hoboken's founder, Col. John Stevens III, and adorned with a gothic-style stone arch. Named after the ancient Greco-Roman prophetesses, it was originally Hoboken's biggest tourist attraction, for the magnesium-laced water that flows from the spring.