The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

The blinking light atop the iconic landmark has been sending secret messages for decades.

Stunningly detailed mosaics in a New York subway station bring life to the Weimaraners of artist William Wegman's work—and to thousands of commutes.

There are lots of hands and feet stamped in the cement in front of Grauman’s Chinese Theater, but Mel left behind something extra.

Hidden inside one of the world's most well-visited zoos is a secret plaque promising eternal life.

Pulled from the rubble of one of the worst modern tragedies, a steel crossbeam became a symbol of hope for New Yorkers.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

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

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

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

This unreal Portuguese palace looks as though it's made from a pile of different castles.

Two standing giants remain as a tribute to Luxembourg's metallurgical past.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

There are owls with glowing eyes in Herald Square.

There must be a pun in this haystack somewhere...

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

A bit of retro transportation flair preserved in the world's largest department store.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

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