A mysteriously abandoned campsite in San Angelo State Park.

A massive 1830s industrial site once known as Czechia's "Iron Heart" has been transformed into a playground of science, technology, and art.

One of the largest-ever mental hospitals now sits abandoned, surrounded by 25,000 unmarked graves.

The architect of this fanciful complex called it an "oasis for humanity and nature in a sea of rational houses."

Swedish mice can dine at the Nuts of Life restaurant or take a date to the amousement park.

A painfully obvious spy house sits right across the street from the Russian Embassy.

A mocking tribute to the past and modern leadership of Prague.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

Six beautiful wooden giants are hidden around Copenhagen.

The site where a nuclear bomb was lowered over 8,000 feet underground and detonated as an experiment in natural gas extraction.

The elegant structure of this 19th century railroad bridge creates an illusion of infinity.

The forest that inspired Winnie-the-Pooh's Hundred Acre Wood can be found outside London.

A statue honors the local legend that the devil helped build St. Mary's church after being tricked into thinking it was going to be a wine bar.

You can see three Irish counties from this Neolithic hillside fort, once the seat of the Kingdom of Ailech.

The pits used to load the nuclear bombs onto the aircraft that dropped them over Hiroshima and Nagasaki at the end of World War II.

From Coke II to Google Glass, this exhibit features some of the most spectacular commercial flops.

In the woods of New Jersey lie the ruins of a munitions village abandoned after World War I and the remnants of a 1920s wooden racetrack.

A whimsical art tower at a Bavarian brewery includes a grotto for its mythical beer-brewing dwarves.

The mysterious headstone of an unidentified bank robber was seen visited, every year, by a woman in black.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

This tiny museum's sizable collection is jammed into a former underground public toilet.

This crumbling 14th century chapel became so unstable the roofing apparently collapsed during a wedding ceremony, narrowly missing the curate's head.