This "City of Books" holds a museum, library, and the complete personal book collections of five of Mexico's greatest thinkers.

Part bookstore, part café, and part forest.

The only castle in North America to ever house European sovereigns.

The 28-foot granite map plots the locations of 40 theaters in New York City.

Salute the leader of the proletariat.

Love, knishes, and best wishes from this legendary Lower East Side bakery.

A popular European tradition makes its way to the states on one of America's most famous bridges.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

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

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

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.

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 U.S. Navy’s preposterously detailed mini battleship took 77,000 hours to complete.

Look closely and you’ll notice that the color changes a third of the way up the tower.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

An overlooked memorial honoring the local Washington residents who died in World War I.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

An easily overlooked memorial to a Ukrainian famine-genocide that killed over 4 million people.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.