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 Eye, Albania
The Blue Eye () is a water spring and natural phenomenon occurring near Muzinë in Vlorë County, southern Albania. A popular tourist attraction, the clear blue water of the river bubbles forth from a depth of more than fifty-metres. Divers have descended to fifty metres, but it is still unclear what the actual depth of the karst hole is.