"New Mexico's Blue Hole gets its name from its sapphire-blue waters that stay at a constant temperature of about 62 degrees Fahrenheit. Popular among scuba divers and cliff jumpers, the swimming hole is open year-round, giving you a chance to explore its underwater corridors even after summer ends. There's also a visitor center with exhibits, a snack bar, changing rooms, restrooms, a gift shop, and a viewing area." - Travel + Leisure Editors