Luray Caverns, originally called Luray Cave, is a large, celebrated commercial cave just west of Luray, Virginia, USA, which has drawn many visitors since its discovery in 1878. The water is that color from copper, and the lighting. Donations go to charities listed on that board. 
Lechuguilla Cave, New Mexico , is the fifth longest cave discovered yet at 120 miles (193 km) long and measures 489 metres (1,604 ft) deep, making it the deepest in continental United States. 
Banff, Alberta Canada 
Reed Flute Cave in Guilin, China was discovered during the Tang Dynasty almost 1,300 years ago.It’s a huge underground cave system with stunning rock formations, stalagmites and stalactites, illuminated with coloured lights. The cave can hold comfortably 1000 people. 
Cheddar Gorge is Britain’s biggest canyon and is found within the Cheddar Caves, where the UK’s oldest complete human skeleton was found in 1903. Known as the Cheddar Man, the remains were estimated to be 9,000 years old.
Križna jama is a cave located in Loška dolina, Slovenia. The cave is particularly noted for its chain of twenty-two subterranean lakes of emerald green water
This underground lake near Macan Ché on the Yucatán Peninsula is one of many that are considered to be gifts from the gods by the Mayans, and therefore sacred.
Wookey Hole Caves is a show cave and tourist attraction in the village of Wookey Hole on the southern edge of the Mendip Hills near Wells in Somerset, England.The caves, at a constant temperature of 11 °C (52 °F), have been used by humans for around 50,000 years. The low temperature means that the caves can be used for maturing Cheddar cheese
Hamilton Pool Preserve is a natural pool that was created when the dome of an underground river collapsed due to massive erosion thousands of years ago. The pool is located about 23 miles (37 km) west of Austin, Texas off Highway 71. One of the most outstanding features of the pool is its 45 foot (14 m) waterfall that spills from the dome above. The preserve is home to some small fish and turtles, which are protected by strict regulation.
