Islands of Wonder

(crickets chirring) (dramatic music) -

Narrator

This pool is a portal to a previously unexplored world. (water whooshing) (suspenseful music) In 2015, divers ventured into a vast network of flooded passages. Over 160 feet below the surface, they entered a truly magical underworld, discovering over seven miles of connected tunnels (uplifting music) and some of the biggest underwater chambers in the world. (water whooshing) But it's what they found inside these caves that was their most astounding discovery, a vast graveyard. The preserved remains of mysterious creatures. Horned crocodiles, a puma-like predator, and even pygmy hippos, but most impressive of all, the skulls of giant lemurs that grew to the size of a gorilla, all now extinct on Madagascar. Their demise coincided with the most disruptive change in Madagascar's long history. Just a few thousand years ago, the arrival of people.