Each year melting snow turns these Austrian hiking trails into scuba zones.

A church of bones, decorated with 40,000 human skeletons.

The Natural History Museum that time forgot.

The oldest wind turbine in Europe, constructed by a group of friends in 1932.

The beautiful baroque library of the Hapsburg empire.

Budapest's Communist-era statues, banished to the suburbs.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

The tallest stationary dunes on Earth also happen to sing.

These mammoth-yet-narrow crevasses in the Earth are perfect for taking an otherworldly swim.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

Extraordinary rock formations in open Peruvian fields.

Mysterious standing stone formations looks like a petrified forest.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A valley of unique erosion patterns lends to a view like nothing on Earth.

In a long-dry lake bed, these groups of massive stone pillars bear a striking resemblance to clumps of everyone's favorite fungi.

From the sky, a kaleidoscope of color brightens the grey landscape of the San Francisco Bay.

One of the most extreme deserts in the world, these snow-free valleys harbor life, despite the hostile environment.

This peculiar lake of pitch is so thick and viscous that one can walk on its surface.

Mount Nyiragongo has erupted at least 34 times since 1882 and is home to the world's largest lava lake.

Mysterious spherical rocks in the semi-desert of western Kazakhstan.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

An abandoned whaling station on an active volcano offers hot springs in Antarctica, surrounded by ruined giants of industry.

A remarkable geological formation resembling a forest made of stone.