This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

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

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

This ancient holy well is older than much of the city that surrounds it.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

This fascinating and poignant museum chronicles every imaginable aspect of Spanish colonialism in the Americas.

This embalmed man is one of the best preserved mummies from the Canary Islands.

Part of the medieval watchtower is displayed in an otherwise ordinary parking garage.

A subterranean relic of the Spanish Civil War hides below this picturesque park.

Stuck in the middle of a modern Madrid city block are the remains of a 19th century sports complex.

This small museum tucked within a subway station holds pieces from Madrid's past.

Earth's rocky history has rarely glittered so brightly as it does in this Spanish museum.

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

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

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

You would never come across this tiny green oasis if you didn't know it existed.

This enormous steel tube is the biggest speaking horn in the world.

Rediscovered in 1992, this abandoned medieval village once flourished by fishing and piracy.

After the construction of a nearby cathedral obstructed the view, the oldest belfry in Belgium was more than doubled in height.

This museum is housed in an unassuming building that witnessed one of the most daring feats of satire in modern history.

One of Belgium's oldest hospitals saw patients from the 13th to 20th centuries before becoming a museum.

This memorial museum chronicles the apocalyptic destruction of the First World War.

Nature is slowly overtaking this disused cemetery on the outskirts of Brussels.