Blue Hole (Big Pine Key)
The Blue Hole is an attraction on the island of Big Pine Key in the Florida Keys. It is an abandoned rock quarry that was used for nearby road fills and Henry Flagler's Overseas Railroad. The water it contains is mostly fresh and is used by various wildlife in the area, such as birds, snakes, alligators, key deer and green iguanas. It is part of the National Key Deer Refuge.
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.