This sprawling, Brutalist estate feels like a city within a city.

Over several decades, one of London’s most iconic city gates was dismantled, moved out of the city, and then moved back.

Near the site where the English Archbishop was born, you can find an emblem in the shape of a pilgrim's badge.

This castle has links to Portugal’s founding and struggles for independence.

A hidden three-foot-wide house separates these two regal churches.

This tile-work piece featuring a chicken riding in carriage is both a remarkable artistic creation and a social commentary of politics and culture in 17th-century Portugal.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

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.

Eat the ultimate iteration of Portugal's most beloved pastry.

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

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

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

Portugal's National Pantheon has a history of curses, collapses and financial problems.

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

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

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Catacombs turned marketplace.

Eighty million natural history specimens call this gargantuan museum home.

This artist's home turned gallery/museum preserves the creator's love of "Eastern" influences.

Order a salt beef-loaded beigel at any hour of the day or night at this East End institution.

Scattered throughout London are ancient remnants of the city's former bounding wall.

Its collection includes a broad array of social, geographic, graphic design, and political history.