The enchanting archway is the only surviving portal into Dublin's lost medieval wall.

One of Ireland's most infamous prisons for rebels including men, women and children.

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

This 23-foot-tall bear stands amid the hustle and bustle of Hamad International Airport.

Feed it cash, get your very own gold bar.

No building in the world leans as far as the so-called “Leaning Tower of Abu Dhabi.”

Whitewashed mosque contains the world's largest carpet.

This enormous sports car themed amusement park is home to the world’s fastest roller coaster.

A preposterously luxurious hotel with gold-plated iPads, Rolls Royce chauffeurs, and a staff that trains by watching "Downton Abbey."

This artificial archipelago was supposed to resemble a map of the world.

The world's largest frame offers spectacular views of the city's past and present.

This remote British Imperial telegraph relay outpost drove men insane.

South Korea's largely symbolic, barely used gateway to the North.

Breathtaking and huge 430 year old maps of Italy.

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

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

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

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

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

France's most famous cemetery, with some of its most curious tombs.

An architect's childhood fantasy treehouse made real.