From what I could gather from a former North Shore resident, the entrance to the cave that goes under the Main Beach is about where you see the edge of the ice. He was diving in warmer weather, of course.

A retired Navy Seal told me this Christmas that he had scuba dived into a cave that he figured went pretty much to St. Thomas Church.

He said he swam until he was at least under the Main Beach.

Anyone else ever done such underwater exploring in Crystal Lake?