Ecosystems

These muddy eruptions are less deadly than actual volcanoes but also more holy.

Once one of the largest producers of pig iron in the world.

In which a local geological marvel becomes a quaint roadside attraction.

Human-made caves excavated to hide a secret society of wealthy pagans.

The arboretum whose marshy soil sucked up the dreams of housing developers.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

Final resting place for hundreds of prisoners of war.

The remains of a 19th century spring, and the site of an infamous unsolved murder.

Civil War dumping ground for the bodies of terrorized Union sympathizers.

This famous city eluded concrete detection until the early 2000's.

The Vatican's secret porn-festooned bathroom was painted in erotic murals by one of the greatest artists of the Renaissance.

A salty red wasteland in Tanzania is a breeding spot for endangered flamingos.

This rocky spread has been squeezed up directly from the bowels of the earth.

Artistic cabins actually grow deep in the Canadian wilderness.

This underground power plant looks more like a super-villian's lair than a public work.

An unfinished rail tunnel that has since been used to house cheese and bats.