A fantastic castle rumored to be the birthplace of King Arthur.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

A small memorial to a deadly night in Serbia that shook the world before it was swept under the rug.

Religious structure known for its sculpted details.

Romania's triumphal arch looks out over Bucharest.

A giant portrait of an ancient king looms over the river.

The growing stones of Romania.

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

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

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

Berlin's old airport.

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

Super-heavy Nazi architectural experiment.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

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

This North Korean pegasus statue was built as a symbol of the speed and perseverance of North Korean workers.

A bizarre collection of gifts to North Korean dictator Kim Jong Il from the despots of the world.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

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

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

A restaurant and observation deck built in a unique broadcasting antenna.