Early Nazi prison for political prisoners.

A museum dedicated to the history of the diamond trade in the Netherlands.

The imposing structure was originally established in 1580 as a military stronghold.

A pillar is all that remains of a church built to honor a peculiar miracle.

Visitors can still take a train to this former train station turned museum.

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

Berlin's old airport.

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.

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

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

One of the largest busts in the world celebrates the German city's erstwhile namesake.

One of Amsterdam’s most popular cultural and recreational complexes is on the site of a former gas works.

A 14th-century church holds a unique monument to a German mathematician who dedicated his life to calculating the value of pi.

A plaque hidden in the law faculty at Leiden University honors the first scientist to make liquid helium.

This stately council chamber hasn't changed since 1545.

People have been placing babies on these lilies for photoshoots since the Victorian era.

This small museum located under the famous cube houses, is home to some 30,000 chess pieces.

Remarkably preserved body discovered in a peat bog.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

Spend your honeymoon where the Devil had his wedding.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

A giant yellow phallus sculpture hidden in the gardens of the Museum Boijmans Van Beuningen.