The only quarter of the Old City not dedicated to a major world religion.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

Museum preserving torture methods from the past.

A safari-themed castle in the South African bush with the largest maze in the southern hemisphere.

This African beach is home to thousands of rare mainland penguins that are known for their annoying voice.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

The word "Watergate" will forever be associated with the infamous scandal in 1972, but this fountain is famous in its own right.

The only tennis court that falls under the jurisdiction of the central bank.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

The "Prussian Versailles" that is as glorious today as when it was built.

The world's largest second-hand graces a clock surrounded by constantly changing flower beds. 

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

A haunting contrast of trains that both saved and took the lives of Jewish children in Nazi Germany.

A church of bones, decorated with 40,000 human skeletons.

One of downtown Berlin's last reminders of its Communist past.

A historic fire call point.

The original burial place of this preeminent 18th-century Jewish philosopher was razed by the Nazis.

Dedicated to the European Sinti and Roma peoples murdered during the Holocaust.

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

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

These markers are used to determine the ground stability of the Strip.