Perhaps the most spectacular grotto along the Algarve coastline.

Considered the birthplace of the Copper Age and Bronze Age, the river is tinted red from 5,000 years of mining.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

A hidden medieval crypt where a famous legend says the devil used to teach black magic.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

Op-art architecture designed for happiness.

Double spiral staircases are not unheard of, but they are very rare.

This strange statue features a bust of the famous composer plopped atop a woman's body.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

A window into a long-lost world, these colorful tiles advertise a long-defunct range of purgative teas, harmless smokables, and diarrhea cures.

A small church ornamented with medieval erotic sculptures.

The most elaborate of 12 medieval arched doorways to the old city of Burgos.

For more than half a millennia, this automaton has rung an hourly bell.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

This small chapel built into rock is the oldest place of worship in Luxembourg.

A masterpiece of modern architecture that caused quite a stir in Paris, recreated in Bologna half a century later.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

Go surfing on this urban wave, "hacked" by local surfers.

A fearsome dragon clings to a corner of Munich's city hall.

The patron saint of spinsters grasps a container of dried blood.

The footprint of a frustrated devil in Munich's Cathedral.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.