Once a thriving business district, this former shopping area is now an urban ghost town in the heart of the city.

Glass and concrete building designed by Albert Kahn.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

This quarter-mile tunnel under the Bluff in Pittsburgh bends at a 45-degree angle.

This cheese shop also houses a museum devoted to Dutch dairy.

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

The world's largest model of our planetary system.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

Opulence and fantasy collide in this royal chair which is supposedly made with unicorn horns.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Hamburgers are intensely proud of their tunnel beneath the river.

The third version of this tall sailing ship sits, rusted and burnt, in Lake Ontario.

For patriotic Russians, this memorial honoring the Soviet soldiers who died liberating Berlin in 1945 is the most sacred location outside of Russia.

One of the oldest continuously-operated gay bars in the United States is allegedly haunted by Truman Capote and Tennessee Williams.

The second oldest continuously operating bar in Louisiana.

This distinctive Crescent City tradition dates back to the days of horse-drawn carriages.

The world-record holder for the longest bridge stretching continuously over water.

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

This float factory takes the mask off of Mardi Gras and lets visitors see where the magic happens.

An abandoned stretch of highway, deteriorating next to the operational one.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

The reconstruction of this prominent building fulfilled a long-written command.