Pilgrimage site for star-crossed lovers.

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

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

The middle finger of modernity.

Thousands of well-dressed mummies below a monastery.

A 16th-century horror show built in a lovely Italian garden.

Architect Le Corbusier built his friend a cubist house to match his impressive collection of cubist art.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

The beautiful baroque library of the Hapsburg empire.

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.

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.

The yawning maw of this pagan visage is said to bite off the hands of liars.

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

Rome's semi-secret peephole vista is also a former Crusader stronghold.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."