VIDEO: What the world's largest cave looks like from a drone

Hang Son Doong in Vietnam is the largest cave in the world - and it's beautiful.

Hang Son Doong in Vietnam is the largest cave in the world - although, amazingly, it wasn't discovered until 1991.

The cave is 5.5 miles long and its largest chamber is 200 metres deep. The cave contains its own rivers and a rainforest with its own ecosystem.