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

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

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

An eerie collection of the surviving structures from a past celebration of the future.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

This small chapel is built of human bones and decorated with a golden skeleton.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

The embalmed remains of the communist leader lie within a custom crystal coffin.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

A historic trade hub teeming with gorgeous architecture, colorful goods, and vibrant designs.

The ancient necropolis houses the immense rock-cut tombs of four Persian kings.

Reaching the "Church in the Sky" requires scaling the cliff face of a sandstone pinnacle with a 650-foot drop.

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

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

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

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

Tiny memorials honor individual victims of the Holocaust.

Berlin's old airport.

Germany's Glienicke Bridge has a shady history of clandestine meetings, espionage, and spycraft.