This Rhode Island mansion was a stand-in for the exteriors of Collinwood in the original "Dark Shadows" series.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

The most confusing clock in New York.

Little Red Lighthouse under the George Washington Bridge.

The homestead of American patriot John Adams.

Foragers once flocked to this big beautiful bayou to hunt for pearls.

At 207 feet, one of the world's longest continuous escalators.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Home of Philip Johnson, one of the 20th century's most influential architects.

A park filled with vibrant mosaics created by more than 300 folk artists.

The tomb of Increase Mather and his son Cotton, influential colonial ministers obsessed with the occult.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

137 graves holding New England's earliest residents.

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.

Three hundred years of preserved Spanish colonial history in San Antonio.

A 131-year-old wunderkammer of Texas history.

A Victorian cemetery in the heart of Brooklyn remains a popular mecca of morbid curiosity.

Narrowest house in Boston.

Turning night into day in Victorian-era Austin to thwart a serial killer.

The site of Paul Revere's historic two lantern warning.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

Lions and tigers and leopards, servals, pumas, bobcats, lynxes, and ocelots... oh my!

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.