Rummu Quarry in Estonia is home to a now submerged and spooky former prison.

This island in Europe lets you alternate between wreck diving and epic animal encounters.

The benefits of altitude diving are clear, but there are some challenges such as the difference in dive tables and more.

Eight underwater photographers share their favorite European scuba diving destinations.

Budapest, where historic thermal baths derive their heat from natural springs deep in the Molnár János Cave.

The amazing story and photos from the underwater exploration of Imperial Russia’s frigate Oleg shipwreck by National Geographic photographer Viktor Lyagushkin.

Tucked away in a Russian region, get to know an underwater secret spot: Vad Lake.

Hammered by Norse gods of old, Iceland's mirror lakes conceal a spreading rift below, a molten gash that cuts to the very center of the Earth.

Looking for an out-of-the-ordinary shark dive? Here are five you probably haven't heard about but should — plus 15 favorites we just can't get enough of.