Divers swim to the bottom of Philippino Lake during the recent Deep Week freediving festival held at a volcanic lake in the Philippines. Some of the world's best divers, including the Australian world-record holder Adam Stern, took part in the underwater event to showcase their deep water diving skills. [Photo: IC]"

Two divers twirl hand-in-hand in the deep water of Philippino Lake in the Philippines. Free divers don't use breathing equipment, and the best of them can hold their breath for a staggeringly long period of time. [Photo: IC]"