This mountaintop observatory is home to one of the world's largest reflective telescopes.

This cave was the former seat of power for two brothers who ruled together as kings.

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

Crossing this suspension bridge feels like walking through the sky, a fitting tribute to the head of the Apollo program.

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

This museum sits on the site of a decommissioned military communications base.

The only remaining Cold War–era Minuteman II missile control center in Missouri.

A small peaceful park and waterfall tucked amid the urban grind of Midtown Manhattan.

A backdoor to Machu Picchu that only the most foolhardy infiltrator would attempt to breach.

This abandoned Olympic skiing facility still bears the scars of the Siege of Sarajevo.

This Chinese museum proves that it's a watermelon world, we're all just living in it.

Mussolini gave Cincinnati a bronze statue of Romulus and Remus suckling at a wolf's teats.

This park in Nagarkot boasts one of the best views in all of Nepal.

Single runway interrupted by a busy road that cuts across its middle.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

These fantastically named natural pools look like something out of a Scottish myth.

France's most famous cemetery, with some of its most curious tombs.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

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

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

The platform atop this verdant volcano was built with the help of a royal elephant.

A sharp bend in a dramatic river canyon cut through red rocks.