jeita grotto, Lebanon

Jeita Grotto, the longest cave in the Middle East, is situated approximately 11 miles (18km) north of Beirut. It consists of two separate, but interconnected, limestone caves, and boasts a length of 5.6 miles (9km). One of the worlds most amazing agglomerations of stalactites and stalagmites, Jeita Grotto is widely considered to be the pride of Lebanon, and featured as a finalist in the New 7 Wonders of Nature competition.

Mulu Caves,Malaysia

The Mulu Caves lie deep in the jungles of Borneo, sprawling for miles below Sarawak’s Gunung Mulu National Park. The sea carved the deep gorges and complex cave networks of the caves limestone system. Designated a UNESCO World Heritage Site in 2000, the Mulu Caves are considered to include some of the planet’s largest known underground caverns and passages. Notable caves are Benarat Cavern, Clearwater Cave, Wind Cave, and Sarawak Chamber, considered the largest known natural cavern in the world.

Puerto Princesa Underground River, Philippines

Situated on the coast of Palaway, about 364 miles (585 kilometers) off the coast of Manila, Puerto Princesa Underground River has recently been designated as one of the Seven New Wonders of Nature. With five miles (8.2 kilometers) of navigable waters, it is considered the longest navigable underground river in the world. Visitors taking a paddle boat tour of the cave will see massive caverns, a huge cave dome, unusual rock formations and the legions of swiftlets and bats that inhabit the caves. Lion’s Cave, Daylight Hole and Kawili Cave are popular with explorers. 

Eisriesenwelt Cave, Austria

Meaning “World of the Ice Giants”, the Eisriesenwelt is a vast limestone and ice cave located inside Hochkogel Mountain in the Austrian Alps. The Eisriesenwelt sprawls more than 26 miles (42 kilometers) through the Tenneggebirge section of the Alps, though only the first half-mile is sheathed in ice. The caves were sculpted by the Salzach River, and its massive ice formations are formed by thawing snow draining into the cave and freezing into natural ice sculptures. Some of the cave’s highlights include the giant stalagmite in Posselt Hall, the Great Ice Embankment, the soaring stalactites of Hymir’s Castle and the stunning Ice Place, located 1300 feet (400 meters) underground.

Skocjan Caves, Slovenia

One of the most important cave systems in the world, Slovenia's Skocjan Cave system was added to UNESCO’s list of World Heritage Sites in 1986. Entering the caves at the foot of a steep gorge below the village of Skocjan, the Reka River runs underground for 21 miles (34 kilometers) through the massive underground canyons, gorges and caverns, surfacing at Monfalcone to join the Timavo River. This underground channel is over 460 feet (140 meters) high, expanding at points into enormous underground chambers, including Martel’s Chamber, the largest discovered underground cavern in Europe.

Reed Flute Cave, China

Reed Flute Cave is a natural limestone cave in the Guangxi province of China. The cave's name is derived from a variety of a naturally abundant reed that grows throughout the area, which can be used to make flutes. Reed Flute Cave boasts bodies of water, extraordinary stalagmite and stalactite formations, and a number of ink inscriptions dating back to the 8th century. The amount of rock formations, as well as their variance of shape and color, has led to the cave being deemed “The Palace of Natural Arts.”

Majlis Al Jinn Cave, Oman

Majlis al Jinn, which translates to “Meeting Place of the Spirits”, is one of the world's ten largest cave chambers. It is situated in Oman, southeast of Muscat, and is notable for its isolated and relatively inaccessible location. The only entrances to Majlis al Jinn are small openings formed by rainwater erosion atop the remote Selma Plateau, which forms the peak of the cave’s magnificent freestanding domed roof. The sheer size of the chamber, when contrasted with its unassuming exterior, renders it a unique natural wonder.

Cave of the Crystals, Mexico

The Cave of the Crystals is a natural marvel in Chihuahua, Mexico. Its main chamber houses some of the largest natural crystals ever discovered, hence the name of the cave. The crystals are composed of selenite, and have formed due to the cave's position over a pool of magma, which saturated the groundwater with minerals. The magma makes the cave unbearably hot after a period, and for this reason it is largely unexplored. Nevertheless it is unquestionably one of the world's most remarkable displays of natural mineral formations.

Waitomo Caves, New Zealand

The Waitomo Caves are located on New Zealand's North Island. The name is derived from the Maori language, and roughly translates to "water passing through a hole". Some caves are extremely accessible, while others may receive only minimal traffic. The caves are natural limestone formations that are over 2 million years old and feature wonderful stalagmite and stalactite formations. However, they are best known for their abundance of glow-worms, a type of insect unique to New Zealand. Thousands of them inhabit certain caverns in the Waitomo system, and their luminescence provides for a beautifully illuminated experience in the Waitomo Caves.

Carlsbad Caverns

Carlsbad Caverns is a series of natural limestone caves located in Carlsbad Caverns National Park, in the Guadalupe Mountains of New Mexico. The most notable chamber is the “Big Room”, a cavern 4,000 ft long and 225 ft high, at its highest point. The Big Room holds some of the Caverns’ most impressive formations, although there are a multitude of other chambers that feature a variety of natural marvels. The Caverns are rich with speleothem formations, fossils, underground pools, and hundreds of thousands of bats, which emerge in a dazzling nightly ritual.