Water

This impressive system of tanks was used to store drinking water as long as 2,000 years ago.

This giant, 83-year-old ship elevator is an engineering feat to behold.

At 72 feet below sea level, it's the lowest commercial airport in the world.

Iran's colorful terraces are a rare geological masterpiece.

No one is quite sure of the origins of these idyllic natural hot springs at an abandoned mountain resort.

The widest waterfall in Europe is a natural wonder and one of the only places where fish are caught in the air.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

A place for ship-lovers to watch the passage of freighters traversing the Great Lakes while learning about their history.

A tiny chapel clings to a precipice above Germany’s gemstone capital.

A collection of heirloom roses tucked in a spectacularly beautiful botanical garden on Lake Atitlan.

An eccentric aristocrat brought these Australian natives to their current Scottish home.

A plaque marks the underground site of one of London's "lost rivers."

A mysterious crater-like pond has a spooky tendency to empty and fill with complete disregard to rainfall patterns.

An abandoned giant glass dome sits in the bay in “the Venice of the East.”

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.