Blue Hole (Castalia)
The Blue Hole is a fresh water pond located in Castalia, Erie County, Ohio, in the United States. From the 1920s to 1990 the Blue Hole was a tourist site, attracting 165,000 visitors annually at the height of its popularity, partly because of its location on State Route 269, about southwest of the Cedar Point amusement park in Sandusky, Ohio.
Portsea Hole
The Portsea Hole in Port Phillip is about from the Portsea Pier. To the north there is a vertical wall approximately long. The wall has small overhangs which are home to plenty of marine life, including the beautiful Blue Devil fish. The Portsea Hole is a very popular boat dive site for recreational scuba diving activities.