Azores: Pico Island – Gruta Torres Lava Tube

Gruta das Torres is a 5km lava tube discovered on Pico in 1990 after some cows fell into it. It has a variety of frozen lava flows inside, and even stalactites and stalagmites (albeit not growing, they were formed when hot lava dripped and exploded in splash bombs). Nature slowly takes over with bacteria and mosses. This site is on the waiting list for the UNESCO World Heritage Site nomination.