The only ancient site that remains on the south bank of the sacred Ilissos river.

This historic structure has been used as a mosque, a barracks, a prison, a school, and a bakery.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

This red London phone booth once stood in front of Buckingham Palace and was used by the queen.

Four-story slides send people whizzing through the math department at this Munich university.

The "Mystery and Company of Merchant Adventurers" is an Elizabethan-era hangout in Moscow.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.