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

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

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

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

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

At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

A fascinating insight into daily life in the Eastern Bloc.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

Tiny memorials honor individual victims of the Holocaust.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

A monument to the man who almost killed Hitler.

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

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

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

A discarded movie prop that was the original monolith for "2001: A Space Odyssey."

There's an exclusive Beefeaters pub hidden in the Tower of London.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The ritual has been performed uninterrupted for nearly 700 years.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.