The petrified remains of 150-million-year-old trees can be seen in and among the houses of the local villagers.

Artifacts showcasing the witchy history of Zambia.

The largest prehistoric ruins south of the Sahara, once a powerful center of international trade.

The stunningly blue waters of these beautiful caves also have a violent past.

An unexpected ghost village lurks on the southeast coast of Tenerife.

The current seat of the Parliament of Andalusia was once the epicenter of the Great Plague of Seville.

This haunting location was featured in the final scene of a classic spaghetti western.

The fragmented remains of a massive public bath connected to the city's water supply.

This small cemetery and its chapel are located in the middle of a traffic circle.

The surviving remnants of a destroyed medieval church now stand in a public park.

Tools, pottery, and mummies showcase the history of La Palma's native people.

Remains of the lost church hide beneath this Spanish Parliament building.

The building hides in plain sight in Ribadavia's historic Jewish quarter.

The mysterious remains of a martyred teenage saint are venerated inside a small country chapel.

This Bronze Age man spent millennia buried in a mine, giving his bones an eerie hue.

Two 2,500-year-old Phoenician boats found on the coast of Spain, giving incredible insight into the ancient maritime traders.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

This Arab fortress was once the largest citadel in Western Europe.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

In Spain, the ruins of a Roman military camp sit along a flooded section of a river.

Five million people are laid to rest here, more than the population of Madrid itself.

The largest medieval water tank on the Iberian Peninsula is preserved beneath the Cáceres Museum.

Despite its grandiose name, this enigmatic first-century void under the town is no cave, and it's possibly not a palace either.

The deserted remains of a luxury hotel turned hospital ward.