More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Known for centuries as the famous Roman emperor's burial place, this monument is actually something else.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

Legend has it that any woman who kissed this statue would soon be married.

Europe’s oldest natural human mummy.

A devastating landslide accidentally created this tourist hotspot.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Pilgrimage site for star-crossed lovers.

The intricate geometry inside this Baroque-style dome was designed to create "terror of the human soul."

One of England's most famous churches hides a pair of little known architectural treasures.

This skewed English house has looked like it's going to fall over for centuries.

An Orthodox church built by the Royal Family for the Russian community exiled to the French Riviera.

An ivy-covered arch bridge dedicated to Tejano music singer and legend Rosita Fernandez.

A statue of a boy looks up at where the famous rival to the Leaning Tower of Pisa once stood.

An early 20th-century bullring converted into a modern shopping center.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

A cemetery in Barcelona's Poblenou district is home to this touching funerary statue, which depicts death in the form of a winged skeleton.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.