Cryptic messages embedded in the New York City sidewalk.

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

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

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

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

Mysterious 500-year-old tapestries depict a unicorn hunt.

One of only two commuter aerial tramways in the United States.

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

Elevated freight railway turned wildly successful urban park.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A little sculpture with a large wardrobe.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

The oldest pub in Ireland may also be the oldest surviving bar in the entire world.

Long tunnels run under the ancient chariot racing circuit to the tower.

An eclectic collection of thousands of items owned by the sculptor Frederic Marès.

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

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

The first memorial dedicated solely to the Black troops who fought for the Union.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

Art deco landmark on the outskirts of Washington, D.C.

Perhaps the most scandalous statue of America's first president.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

Largest Roman Catholic church in North America.