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

A Franco-era dam flooded (almost) everyone out of this centuries-old Aragonese town.

The morbid items in this small and hidden museum are not for the weak stomached.

This house's itty bitty size means no humans allowed.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

A Spanish forest is filled with mysterious stone carvings.

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

Turntable anonymously received orphans, alms, and groceries.

A stately palace has been converted into the world's largest cannabis museum.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

Bacteria and algae give the salty water its bubblegum hue.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

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

This cemetery features modernist statues as strange as its name.

A beautiful but toxic fountain of mercury.

The growing stones of Romania.

A spooky spot along the road where things mysteriously seem to move uphill by themselves.

This enormous abandoned prison was once dubbed the "Bastille of Romania."

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

Gigantic Romanian salt mines used to heal respiratory conditions.

Known as the Hintz House, this medieval pharmacy has been an apothecary's haven for nearly 450 years.