These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The remains of a Canadian train crash are now mouldering beneath layers of rust and graffiti.

Caves that can't seem to quit producing the remains of prehistoric humans.

Home to some of the oldest hominid fossils ever found.

This dramatic rail curve was once the target of a failed Nazi attack.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

The floorboard scrawling of a tragic madman is on public display outside a Paris hospital, much to the dismay of its opponents.

The programmatic glory of LA's giant whiskey barrel building has become an upscale reminder of the city's kitschy roadside past.

This semi-secret storybook hedge maze is also the oldest garden in the city.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

The soulless eyes of 82 bronze children stare on forever in remembrance of a horrifying World War II massacre.

A monument to the art of slicing people open.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

Oslo's historic toboggan run has been letting thrill seekers slide from train stop to train stop for over a century.

One of the largest amphitheaters in Europe is a former Nazi gathering place that still stands today.

Pick up all of the cosmic knick-knacks under the sun or take a creative writing course, all offered in this novelty storefront.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.