The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A museum that cashes in on its infamous little people while teaching you a thing or two about the Irish fey.

You feel like you're in a forest, but you're actually walking amidst the branches and trunks of a single giant tree.

Once called the Jersey Lilly, this former saloon was the domain of infamous Judge Roy Bean.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

You can spend the night in Dr. Frank-N-Furter's castle.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

This restaurant was removed from the famed sister ship of the Titanic and placed within a hotel.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

2300-year-old Roman road connecting the empire.

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

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

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.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

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 ruins of this monumental city founded by the first Roman Emperor are strangely overlooked by most travelers.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.