A trash dump made beautiful by nature's power.

Centuries-old bridges grown from tangled roots.

The first declared National Monument in the United States.

The ghostly remains of an accidental sea.

This lab's maddening silence is good for business but bad for sanity.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A natural gas leak provides a flickering flame beneath a waterfall.

The most alien-looking place on Earth.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

Enormous lake at the bottom of a unique cave system.

Hidden beneath the streets of London is a secret subway that only carried mail.

An Australian lake whose pink hue defies scientific explanation.

On the Oregon coast there is a natural hole that seems to be draining the sea.

A walk through the historic city center, under the streets of Seattle.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

Two stunning 17th-century libraries and a cabinet of curiosities.

Towering basalt columns, a creation of fire and ice.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Odd outsider art installations surround a Gold Rush-era ghost town.

Monasteries on rock pillars, once accessible only by frayed ropes.

The largest of London's subterranean rivers and once a mad, bad center of London life.

A battle between nature and architecture in the Cambodian jungle.