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

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.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

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.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This haunting monument honors the victims of 9/11.

This poignant display is now a memorial to these regionally extinct species.

Imagine having a street run right through your home, or better yet, a historic bridge three stories high.

This sculptural piece by the artist Tom Otterness doubles as a jungle gym.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

Salute the leader of the proletariat.

Check out the underground party scene at the "Burning Man of Brooklyn."

This secluded ruin was once a home for exotic plants.

Behind a bodega is a small museum of relics and ephemera showcasing the history of New York.

One of New York's best collections of pinball is hidden in a secret bar in the back of this laundromat.

This city park was once a lookout point for George Washington’s army during the Battle of Brooklyn in 1776.

This former crime corner has been turned into an eclectic community center.

Underneath the bustling city streets, a hydroponic farm grows unique herbs in an urban oasis.

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

This simple Manhattan salt house is artfully shaped... well, like a giant granule of salt.