This large copper bolt represents the benchmark for measuring sea levels in most of Europe.

A rare tour of an aristocrat's private home reveals valuable 17th-century paintings from artists like Rembrandt.

The attic of a four-century-old canal house hides a clandestine church.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

Sky ships, planes, and portraits left as unique tokens of hope and thankfulness.

Monumental sculptures guard many of the graves, transforming this necropolis into an open-air fine art museum.

A unrivaled and rather horrifying collection of wax dermatological models.

The hollow trunk of this 650-year-old tree was used as a hideout by two Jewish brothers during World War II.

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

Dead weights honor the dead of Portugal's fishing industry.

A city built from mud and known as the "Manhattan of the desert."

A sacred lake composed of over 300 separate pools of highly concentrated minerals.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

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

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

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

The Twisted Trees of Alticane are an unnerving grove of Quaking Aspen, apparently mutated from a single source, giving them a twisted and unnatural appearance.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

An explosion of natural color known as "the river that ran away from paradise."

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

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

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

An eccentric garden of sculptures crafted in India decorate an Irish green space dedicated to Alan Turing.

Every color in the rainbow awaits.