Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

A Spanish town built into the cliffs.

The world's largest wooden structure.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Montreal's colorful subway station shows its support of the local LGBT+ community.

Small ship votives hang from the vaulted ceiling of this port-side church with a Latin inscription on the wall.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

This giant monument of the RCA mascot is a beloved fixture in Albany, New York.

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

The site of the deadly Triangle Shirtwaist Factory Fire.

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

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

Rummage through this sunken ship, but leave your scuba gear at home.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

An artist's cute bronze subway sculptures belie his violent artistic past.

Cryptic messages embedded in the New York City sidewalk.

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

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.