These 400-year-old ruins are all that's left of the monastery where Ines de Castro was assassinated by the King of Portugal.

A horse statue that receives constant makeovers from graffiti artists and locals.

The hidden ruins of an old hydroelectric plant reclaimed by nature.

A 16th-century Andalusian palace.

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

Oliver Cromwell marched his army over this narrow bridge to victory at the Battle of Preston in 1648.

A stained-glass window from the 15th century offers a vision of the end of the world.

One of the shortest streets in York has an especially odd name.

Makers and sellers of the original and finest York Ghosts.

This network of narrow, medieval passages has the most delightful name.

Follow the original medieval paths that wind through this intriguing section of the city.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The world's oldest bookshop still in operation.

One of the largest Roman settlements in Portugal.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

The view that inspired the scenes of Dracula's first landing in England.

Legends say that this small island was the final resting place of the Welsh saint of lovers.