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.
Cyanea dolichopoda
This Hawaiian lobelioid was discovered in the Blue Hole, a valley on Kauai near the Wailua River. The Blue Hole is deep, nearly surrounded by steep cliffs up to 900 meters tall, and wet, a very high rainfall area filled with waterfalls. Only four plants were ever found, three juvenile specimens and one plant just reaching flowering stage. Because the plant was so obviously an unknown species and was apparently on the brink of extinction, it was given a name. It was not seen again after 1992.