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.

The London pub overlooks where the Mayflower was moored before setting sail for the New World.

A top-secret bunker now turned museum, is an eerie look at what life would have looked like in the event of nuclear war.

Founded by a man who called himself the greatest hunter alive.

Medical museum featuring a number of excellent medical models.

A local landmark with generations of spraypainted messages, and more being added each day.