It rises 4,750 metres (15,600 feet) above the ocean floor, and has a central volcanic plateau. Like many of the southern islands in the Cooks, it's surrounded by cliffs of fossilised coral, called the makatea, in this case 60 metres (200 feet) high. It looks beautiful in the left hand picture below, but the coral is razor sharp.
Mangaia is also honeycombed with amazing caves like the one pictured centre with its owner, Teremanuia Taukakuma. And inside, there are stunning natural rock formations like the ones on the right below.