Hang Son Doong, Vietnam
Hang Son Doong is huge. Lying hidden from sight until recent times, the largest cave on Earth wasn’t discovered until the 1990s. Since then, it has beckoned adventurers keen to explore an underground world that is breathtaking in its scale. Like travelling to a place from another planet, heading deep into Hang Son Doong’s immense halls is a unique experience.
You could fit an entire New York City block down here — including the tallest towers and skyscrapers. But there’s rather more to awe-inspiring Hang Son Doong than its size alone. Light streaks in from sinkholes on the surface — helping lush vegetation to thrive underground in a unique environment that must be seen to be believed. Look out for giant stalagmites that measure up to 70 metres in length, a fast-flowing subterranean river that rushes past and the clouds that form when moisture condenses on the cave system’s distant ceiling.