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

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

Eighty million natural history specimens call this gargantuan museum home.

Hidden beneath the streets of London is a secret subway that only carried mail.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Experience what life was like in Ireland during the Viking and medieval ages.

Banished from town, this local jester concocted a clever return.

This memorial museum chronicles the apocalyptic destruction of the First World War.

The bronzed skull of a beheaded traitor was affixed to the city gate in the 17th century.

Climb inside an iron crystal magnified 165 billion times its normal size.

Amsterdam's Red Light District leaves little to the imagination.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

A restaurant and observation deck built in a unique broadcasting antenna.

This monument to one of the largest science fiction games of all time bears the names of hundreds of thousands of players.

A giant bug impaled on a 75-foot-tall needle.

This whimsical statue dumps water on its head to symbolize knowledge flowing into his brain. Or maybe booze.

England's most famous front door has an accidental doppelganger.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

The television series' iconic giant foot was borrowed from this classical painting.

The largest of London's subterranean rivers and once a mad, bad center of London life.

These imposing walls and towers look more like the ruins of a fortress than a monastery.

Once the longest bridge in Ireland, this rusting span sits abandoned and overrun by nature.

This historical Netherlands fortress still bears the marks of its single siege.