This outdoor library provides around-the-clock access to around 7,000 books.

Once a bustling cotton factory, this early 20th-century building is now home to a thriving artspace.

This strange, small castle on the bayou has withstood the test of time and weather.

This 45-story tall abandoned skyscraper is the third tallest building in New Orleans and Lousiana.

The oldest family-run restaurant in the United States is a living museum of New Orleans dining history.

This concrete residential area doubles as an open-air gallery.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

Believed to be the oldest active college baseball field in America.

A 200-year-old bar is all that remains of one Mississippi River town's rough-and-tumble past.

This now-deactivated naval base defended the Florida coast for centuries.

This extremely narrow tenement boasts a maximum occupancy of just two.

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

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

This tremendous timepiece was once the largest cuckoo clock in the world.

Berlin's old airport.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

Tiny memorials honor individual victims of the Holocaust.

One of the world's heaviest musical instruments towers within a popular urban park.

After a nearly successful attempt on Hitler's life, the conspirators met their fate in the courtyard of this Berlin building.

Metro station with a claim to rock n' roll fame.

Cold war icon and onetime "hole" in the iron curtain.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

A preserved Nazi labor camp now has a Holocaust museum on site and memorials to the thousands that died while imprisoned at the camp.