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.
Blue Lake (New South Wales)
The Blue Lake is one of only four cirque lakes found in mainland Australia. The other three, Cootapatamba, Albina, and Club, are shallower and are held entirely by terminal moraines. Blue Lake's valley contains the best-developed glacial features in the Kosciuszko National Park alpine area of New South Wales. It was recognised as a wetland of international importance on 17 March 1996 when a area, comprising the lake and its surrounds, including nearby Hedley Tarn, was designated Ramsar Site 800 under the Ramsar Convention on wetlands. The lake lies within the Australian Alps National Parks and Reserves.