Rivers of cattle blood gone, a strange Escheresque building remains, the last of its kind.

A tunnel dug through the side of a mountain by hand provides convenient yet death-defying access to a small village in China.

This legendary city has been a tourist attraction for centuries.

A spectacular cave and a beguiling lake.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

The hallucinogenic center of the ancient world.

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

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

A giant portrait of an ancient king looms over the river.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

This solitary monastery may hold the remains of Vlad the Impaler (but probably not).

Moss and stone turn this waterfall into an otherworldly liquid veil.

A small town Romanian cemetery filled with darkly humorous gravestones.

This massive underground salt mine now holds a sci-fi theme park in its depths.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

A harrowing trail up a mile-high mountain.

Not one, not two, but three natural bridges remain in this captivating spot post-sinkhole.

Ruins of an early Roman Christian church dating back to the 4th to 5th centuries.

Rock carving created 1,300 years ago 75 feet off the ground.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

An ancient Thracian city where fire rituals were practiced on the largest cult altar in Southeast Europe.