The tunnels are extremely small with an average height of between 1m and 1m 30 so, being as I'm 6ft 2" (185cm), there was no way I was going down! If you can fit, it's still probably not a great idea to go down if you suffer from claustrophobia!
Crawling the tunnels-the ultimate kick?
Crawling the tunnels can be dangerous. The tunnels are very small (Height 120cm, width 80cm) which is not much, especially for "big and tall" Westerners. Whilst the risk of getting stuck may be fairly small, it is not recommended for claustrophobic people. Furthermore I would not advise people with asthma or heart problems to use them. One of the tunnels the guides do with tourists is about 120m/360ft long and descends to about 9m/27ft underground. It gets quite hot and sticky. The tunnels are not lit and various fauna inhabits them. Not recommended for small children either!