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 Mountain (Pennsylvania)
Blue Mountain Ridge, Blue Mountain, or the Blue Mountains of Pennsylvania is part of the geophysical makeup of the Ridge-and-Valley Appalachians in the U.S. state of Pennsylvania. It is a ridge that forms the southern and eastern edge of the Appalachian mountain range spanning over from the Delaware Water Gap as it cuts across the eastern half of the state on a slight diagonal from New Jersey tending southerly until it turns southerly curving into Maryland, and beyond.