Son Doong Cave, Vietnam
Son Doong cave is a newly discovered cave that was only found in 2009 when a man who walked through the forest every day almost fell into the cave when the ground beneath him started crumbling.
Spanning about 9km in length and about 150m in height, it has been crowned the world's largest cave since it was discovered.
Pak Ou Caves, Laos
Being an easy day-trip from Luang Prabang, Pak Ou is a popular and well-known attraction because of its thousands of dusty little Buddha statues - deposited by pilgrims over several centuries - are lots of fun to discover by torchlight in the shallow riverside caves. You can reach Pak Ou by road, but the 1.5 - 2 hour boat trip along the Mekong is much more enjoyable, with longboats leaving Luang Prabang throughout the morning, starting at around 8.30 am.
Sarawak Chamber, Malaysia
As the world’s largest cave chamber, it is no wonder that Sarawak Chamber is a popular destination amongst travelers. This underground hollow is so gargantuan that it is known to be able to fit several Boeing 747 aircrafts in it. It is also part of Gua Nasib Bagus (Good Luck Cave) which is tucked within Gunung Mulu National Park, a UNESCO World Heritage Site.
A visit to Sarawak Chamber is certainly not for the faint-hearted; expect a long hike up along the river, some swimming and even traversing along a steep boulder slope.
Sky Caves of Mustang Kingdom, Nepal
If you ever go to Nepal, you have to try and visit these one-of-a-kind caves. Carved and chiseled on the Himalayan gorge about 47m above the ground, these Sky Caves which were made by men, are some of the most interesting caves around, simply because of the way they must have been built.
Because it is so high up, the only way they could have been dug was from above. Archaeologists have found old eroded murals in the caves but have yet to decipher how they came about to be there. While it sure is a sight to behold from below, it remains a mystery to why these caves were built in the first place.
Masuda-No-Iwafume, Japan
Located in Asuka, a certain rock structure nestled in the forest has left so many locals with confusion over what it is purpose once was. Not only is the purpose unknown, but the material of it makes it almost impossible to have been built by ancient technology.
Its appearance consists of a carved mound with two holes in the centre, going through to the ground. The structure also does not fit with the style of the Buddhist shrines and temples in the surrounding area, which adds to the confusion of its origin. To this day, the rock formation remains a mystery that has yet to be solved.
Pindaya Caves, Myanmar
A series of eerie limestone caverns filled to the roof with at least 8,000 images and statues of Buddha, this sacred site is currently believed to date back to the 1750s. The Buddhas represent an incredible range of workmanship and styles from all over Myanmar, having been donated by rich and poor pilgrims throughout the last 250 years.
To enter the caves, pilgrims must first bravely pass a Disney-worthy giant model spider with huge pointy teeth. The dedicated then climb an intimidating flight of some 700 steps, which lead up the limestone ridge overlooking Pone Taloke Lake, a pilgrimage is not meant to be easy.