The prototype for all Nazi concentration camps.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

Bullet holes in the church wall are a reminder of the violence that followed the assassination of a high-ranking Nazi officer.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

The soulless eyes of 82 bronze children stare on forever in remembrance of a horrifying World War II massacre.

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

Created as a "model concentration camp" to hide Nazi atrocities from the international community, this former camp-ghetto now holds a museum and memorial honoring the lives lost within.

Today this former Nazi concentration camp stands as a poignant memorial to the victims of fascism, and a warning from history.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

The largest airborne operation in history was launched to capture this bridge.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

A statue honors the children who fought Nazis in Poland.

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

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

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

Tiny memorials honor individual victims of the Holocaust.

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

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

The only remaining U-boat that is still floating never actually saw any action in World War II.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.