The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A marvel of Byzantine engineering under the streets of Istanbul.

One of the newest mosques in a city filled with thousands.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A cocktail lounge decorated like an American dive bar, in honor of the legendary author Ernest Hemingway.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

The video game-themed street art first popped up in the French city.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The arch that celebrated the completion of the Lincoln and Victory highways.

What began as a prominent Burning Man art piece is now an iconic symbol of downtown Reno.

A hidden garden of stones engraved with scriptures, a Joseph Smith Sphinx, all carved by one man.

A technicolor place of worship for Elevationists.

Overlooking the Colorado Convention Center is this giant sculpture made from thousands of triangles.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

The palatial McDonald's that inspired Wesley Willis.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.