Take a look inside the world's largest cave

Take a look inside the world's largest cave

Son Doong Cave in Vietnam – which is so big it contains a jungle and a river – is now open for public tours. But don't expect it to become crowded: just 224 tourists will be permitted to visit this year

http://www.theguardian.com/travel/gallery/2014/jan/14/take-a-look-inside-the-worlds-largest-cave