A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A complimentary beverage is offered to the bodega's resident rodents every day.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This small island, a byproduct of 19th-century canal construction, is now home to a charming Japanese garden.

Go inside to really appreciate this 500-year-old technological masterpiece.

According to tradition this is the oldest church in Venice, but its actual age is a mystery.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

A reconstructed medieval gateway that was the magnificent entrance to the capital city dating back to 1037.

A unique bridge with an equally unique view.

These paved rills bring freshwater into Altstadt and could spell wedding bells for whoever stumbles into the waters.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Hamburgers are intensely proud of their tunnel beneath the river.

The fairy tale castle of the "fairy-tale king."