A wall of chewing gum moonlights as collective art.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

This cheese shop also houses a museum devoted to Dutch dairy.

An unsettling sculpture of a boy hanging out in a street in Ghent has been baffling visitors for years.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

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

The shortest in the world, this landing strip stretches a mere 1,312 feet before steep cliffs on either end plunge into the Caribbean.

This colorful gate stands as an entrance to the walled city of Old San Juan.

A sanctuary for sickly, stray, or wounded donkeys.

This living labyrinth made entirely of thorns is filled with art.

A safe place for the wild donkeys of a hot vacation destination.

They squeal, they nosh, they look like predators.

In paradise, feral pigs have claimed an island all to themselves.

A 220-foot deep watery drop-off, filled with marine life.

Meant to be a lavish presidential home, the palace became a symbol of the fall of South Vietnam.

This historic spot was where America's involvement in the Vietnam War officially came to an end.

Submerged lava formations create incredible waterworks.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

This indoor ski resort has a mountain contained inside a mall.

A preposterously luxurious hotel with gold-plated iPads, Rolls Royce chauffeurs, and a staff that trains by watching "Downton Abbey."

A network of ancient Egyptian tombs built into the cliff face along the Nile.

The largest known Ancient Egyptian obelisk.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.