A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

The earliest known map to show America, discovered by accident at a Paris bookshop.

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

Commonly acknowledged as the only public monument to the Devil himself.

A lush indoor jungle fills this bustling Madrid transportation hub.

This lucky bronze frog was gifted to Madrid by a casino.

An ancient Egyptian temple in the middle of Madrid, Spain.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

An enigmatic monument to the Irish revolutionary who plotted an uprising against British rule.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

This courtly monument celebrates an influential comedian who turned taking the piss out of the powers-that-be into an art.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

One of Ireland's most infamous prisons for rebels including men, women and children.

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

The ruins of a church destroyed by both the Great Fire of London and the Blitz, now turned into a peaceful garden.

This striking statue brings a scene from the African savannah into central London.

This religious museum resides in a church crypt next to the founder's house.

The final resting place of a German diplomat's beloved companion.

The medieval woodcut-style artwork chronicles life in medieval London.

On the eve of a condemned prisoner's death, this bell rang 12 times outside their cell.

The "beautiful" equation predicting the movement of all electromagnetic particles is engraved in front of Newton's tomb.

This bewitching Babylonian goddess haunts a hallway of the British Museum.

A sculpture outside London's oldest cathedral honors the Mohegan chief who died while petitioning the king.