An ancient and majestic fortress that played an integral role in Portugal's road to independence.

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

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

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

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The world's largest wooden structure.

America's first public mental health facility.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

Paris' linguistic guide to the international language of, yes, love.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

A German apartment building hosting as many trees as human occupants.

The works of poetry's biggest names grace the walls of the city of Leiden, all carefully painted by hand.

A trio of red, white, and blue stones embedded in the streets of Leiden are markers of medieval territory and law.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.

Fantastic views and thousands of love locks.

A fake medieval village in the middle of Turin.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

France's most famous cemetery, with some of its most curious tombs.

Famously misunderstood wonder of the ancient world

The celebrated eyesore created by starry-eyed sweethearts.