Enigmatic Eerie Underworlds: The Most Unusual Caves on the Planet

The first hall of Phraya Nakhon cave in Thailand has a “frozen” waterfall of stalactites and stalagmites. The ceiling of the second hall collapsed during an earthquake in ancient times. Its walls are covered with plants and stalactites, and there are steps along the walls which tourists can use to go down 65 meters. At certain hours, sunlight enters the cave, illuminating a small temple built by King Rama V (reigned in the late 19th and early 20th centuries).

On the walls of the bizarre grottoes of white limestone at Marble caves in Chile you can see the glare of sunlit blue water. Unusual deep tunnels are believed to have been formed by waves.

The cave of crystals in Mexico has become famous thanks to the giant deposits of selenites.The largest ones reach 11 meters in length and four in width and weigh up to 55 tons. It is impossible to stay in the cave for longer than 20 minutes - the air temperature there is about 58 degrees Celsius - due to a magma cavity that heats groundwater.

Since ancient times, this cave has been used for gathering reeds which served as a material for making flutes. In its grottoes, one can find quaint and beautifully illuminated stalactites and stalagmites. The cave earned the name of the "Palace of Natural Arts".

Batu Caves, located near the capital of Malaysia, Kuala Lumpur, are about 400 million years old. This place is famous not only for ten underground rooms with statues and murals, but also for a Hindu shrine. The figure of god Murugan, the second son of Shiva, is rising 43 meters at the entrance of the cave. Inside, there are many bats and pesky monkeys. In winter, a festival is celebrated here during which its participants must be cleansed of sins through pain. At the ceremony, believers pierce their cheeks and tongue with thin hooks and attach fruit to them.

On the walls of the New Zealand luminous cave Waitomo you can find petrified remains of ancient marine organisms. There was once an ocean, but the water has long receded, and it is dark and humid in the underground grottoes even now - ideal conditions for the life of the unique Arachnocampa Luminosa fireflies. Their secretion produces a glow when exposed to oxygen. To see this miracle, tourists come here from all over the world.

Barton Creek cave in Belize can only be reached by canoe. In the similar fashion, Mayan tribes travelled there more than two thousand years ago. In the underground halls, they held ritual ceremonies and buried relatives. Archaeologists have found the remains of pottery and human bones in the cave.

Mammoth Cave is the longest not only in the USA, but in the entire world (spanning more than 587 kilometers). It is located in the eponymous national park in Kentucky. Cavers have found several graves and mummies of Native Americans there. Now, thousands of bats live under its arches, and blind fish and crayfish swim in the underground rivers.

Cango caves in South Africa have paintings that are several thousand years old. For tourists, several halls are open with bizarre natural sculptures made of stalactites, including a grotto called the "Organ Hall", with a stalactite shaped "organ" in it.

Melissani on the Greek island of Cephalonia is called a cave of nymphs. Archaeologists have found figures of Pan - the deity of hunters - here and a disk with the image of dancing girls. According to a legend, the nymph Melissani fell in love with Pan, but her feeling remained unrequited, and the lake filled with tears. It is believed that if lovers simultaneously dip their hands into the water, their life will be happy. If single people perform this ritual, they will meet their soulmate. The reservoir occupies about a third of the cave. It is located in the open air - in a well formed due to the collapse of the cave's ceiling during an earthquake, about 20 thousand years ago. The colour of the water in the lake depends on the lighting and changes from light turquoise to dark green.

Skaftafell ice cave is located in the eponymous national park in Iceland. It is formed by centuries-old layers of frozen water. The ice here is sapphire-coloured and so dense that there are no air bubbles at all.

Son Doong cave in Vietnam is at least five million years old and is considered the largest on the planet. It has its own jungle, and the temperature difference here sometimes creates clouds and fogs.

Also called the Black Devil cave, Koshkulak cave in Russia's Khakassia was a ritual spot where the ancient Khakas people made sacrifices (including human) to their deities.

Kungur ice cave is a unique geological sight and one of the largest solutional caves in the European part of Russia.