A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

Washington's iconic carousel has a nice piece of Civil Rights history.

The hidden ruins of a mill that is linked to an attempt to assassinate the vice president of the United States.

There must be a pun in this haystack somewhere...

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

One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A rehabilitation center for some of South America's most unique and endangered animals.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

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

At the site of a graffiti artist's murder, fellow artists gather to pay homage.

Home to 23 voluptuous and instantly lovable sculptures by one of Latin America's most celebrated artists.

Two identical statues by Fernando Botero, one blown to pieces in a terrorist bombing, the other donated as a gift for peace.

This unassuming passageway played a key role in one of the most important events in U.S. history.

Built in 1815, the stabilized ruins of the grist mill and sawmill are now gated, but interpretive displays on the features and functions of the mill preserve its history.

Stunningly detailed mosaics in a New York subway station bring life to the Weimaraners of artist William Wegman's work—and to thousands of commutes.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

The longest continuous underwater road in North America was built at the insistence of Franklin Roosevelt.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

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

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

These unusual rooms on wheels are holdovers from the 1960s.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

Pilgrims each carried a brick to the top of Mount Monserrate to help build this historic sanctuary in Colombia.