Northern Ireland's Brobdingnagian stepping stones.

This Italian-style temple replica has been threatening to fall off the Irish coast for hundreds of years.

The world's largest reflecting pool is just two centimeters deep.

This Bordeaux parking garage has 712 indoor spaces, and one outdoor.

In 1927, a biplane disappeared while attempting to complete the first non-stop transatlantic flight between Paris and New York City. This memorial stands at the last place it was seen.

This place bears witness to the loss of many lives during WWII, and stands in stark contrast to the American Cemetery.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

In France, a medieval-style home pays homage to an intrepid explorer who discovered Québec.

The bust of Romania’s most notorious ruler, Vlad Dracula aka "Vlad the Impaler," keeps watch over the ruins of his medieval court.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

A coastal French town said to have been visited by Jesus' disciples is a major pilgrimage center for Catholic Romanis.

The world's largest solar furnace uses 10,000 mirrors to concentrate the sun's rays to generate power.

This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.

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

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

A haven for book enthusiasts across the street from Retiro Park.

A lush indoor jungle fills this bustling Madrid transportation hub.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

This enormous censer uses a pulley system installed over 400 years ago.

A historic Christian shrine nestled within a spectacular natural cave.