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

An underground city of salt.

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

The stone labyrinth in this New Orleans city park was laid to symbolize healing in the wake of Hurricane Katrina.

Formerly known as National D-Day Museum, this collection commemorates the battles of Normandy and WWII.

New Orleans' famous cemetery, located on the site of a former race track.

This historic "City of the Dead" lies prominently in the center of New Orleans' famous Garden District.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

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

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

This massive blockhead sculpture hides an entire library.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

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

San Francisco's newly reopened hands-on science museum.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

A rare set of strings by famed instrument maker Antonio Stradivarius is on display in the Royal Palace.

Commonly acknowledged as the only public monument to the Devil himself.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

An ancient Egyptian temple in the middle of Madrid, Spain.

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

The world's second largest single-dish radio telescope, once used to contact E.T.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.