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

The highest peak in mainland Spain is said to be the final resting place of a Muslim king.

Royal burial place of the kings of ancient Britain.

This one-time health resort was used by aristocrats around the world.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

A striking symbol of the Bulgarian capital.

"Holy Wisdom" overlooks the city that became its namesake.

A vast Communist-era exhibition space in the Bulgarian capital.

This historic black and white monastery is one of Bulgaria's architectural jewels.

This Georgian mansion blends historical significance with an impressive art collection within picturesque surroundings.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

This oft-overlooked public artwork depicts another Warwickshire legend.

Every hour on the hour a naked heroine and her leering foil appear from this giant cuckoo clock.

The bombed out remains of the old church were kept intact next to the new one, as a reminder of the futility of war.

A 17th-century church is nestled within the walls of a 15th-century ruin.

A misunderstanding gave this 18th-century racehorse a most amusing name.

A remarkable medieval structure born from a 14th-century disaster.

The oldest of the three remaining bridges in England with buildings on top of them.

Remains of a keep that was built shortly after the Norman conquest of England.

Legend says this demonic carving inside a medieval cathedral was one of Satan's minions.

The sanctuary seems to either float atop the water or sink into the dirt, depending on the water level.

Hundreds of huge, centuries-old horseshoes adorn the walls of this nontraditional 12th-century castle.

A labyrinthine underworld of tunnels and caverns hides beneath the city.

There's a labyrinth of medieval chambers hidden deep below a 15th-century pub.