When it comes to the worlds longest caves you might imagine a super long underground dome that is measured from side to side. In truth, all these caves are small, wiggly caves that often double back on themselves and pretty much impassable unless you are a cave diving expert. But that doesn’t stop them from being record-breaking, it just means we will need a lot more than a tape measure to record their lengths…
The Ten Longest Caves in the World and Where to Find Them
10 – Hölloch in Switzerland – Estimated Length: 203 Kilometres – 126 Miles
This super-long cave system was once called the “hel” cave which in local dialect means slippery and that is apparently exactly what it is.
9 – Clearwater Cave in Malaysia – Estimated Length: 215 Kilometres – 133.8 Miles
Not only impressive by length, it is also enjoyable to go through it by boat for almost a mile in! It is said to take about 30 mins, but I would imagine it is definitely worth seeing.
8 – Lechuguilla Cave in the United States – Estimated Length: 223 Kilometres – 134 Miles
Not only is this cave system impressively long, it’s also a impressively deep cave at 1,604 feet from the highest point. Unlike many other cave systems, this one was formed from the bottom up by sulfuric acid caused by nearby oil deposits.
7 – Wind Cave in the United States – Estimated Length: 230 Kilometres – 143 Miles
This is said to be the most complex rectilinear maze cave in the world and has limestone deposits that are the thickest in the world at a mind-blowing 275-325 feet (84-99 m) thick.
6 – Shuanghedong Cave Network in China – Estimated Length: 239 Kilometres – 148 Miles
This stunning gypsum and dolomite cave has carbon dioxide levels recorded at over 400ppm! What does that mean? It means its warm in the cave all year round and anyone entering it without a gas mask and breathing equipment would be dead within just a few hours.
5 – Optymistychna Cave in Ukraine – Estimated Length: 260 Kilometres – 162 Miles
This impressive cave system was discovered by a group of speleologists in 1966. What is so unique about this cave is there are several small lakes within the cave system, each one at different levels of height.
4 – Sistema Ox Bel Ha in Mexico – Estimated Length: 270 Kilometres – 168 Miles
This cave was only considered to be half its current recorded length until just 20 years ago a joining, longer cave system was found. Even at half that measurement, it is pretty impressive.
3 – Jewel Cave in the United States – Estimated Length: 311 Kilometres – 193 Miles
This cave was discovered because 2 brothers Albert and Frank Michaud felt cold air shooting out of a hole in the ground. It then took them another 13 years just to map the first 10 miles of it!
2 – Sistema Sac Actun in Mexico – Estimated Length: 347 Kilometres – 215 Miles
Once upon a time, this was considered to be the longest cave in the world, but due to more accurate measurements of our next cave, the title was taken off this nevertheless still impressive cave.
1 – Mammoth Cave in the United States – Estimated Length: 652 Kilometres – 405 Miles
The majority of the mapping of this cave and indeed its length measurement was done by a group of slaves in 1791! While more exact measurements are done with better equipment the measurements the slaves did was still accurate down to just 50ft in error!