A small Second Empire-style building is one of only seven remaining lighthouses on the Hudson River.

The Hudson River School comes alive at this palatial estate.

The schoolhouse where Jesse Merwin, the inspiration for the "The Legend of Sleepy Hollow" character, once taught.

A 13,000-year-old mastodon skeleton was found during the construction of a 19th-century New York mill.

The original Uncle Sam was actually a New York meatpacker who is buried under this historic grave.

This stained glass window designed by Tiffany Studios is hidden behind the circulation desk of a public library.

This relic of 19th-century infrastructure is one of the few remaining coal gas storage tanks in the U.S.

A man used his Civil War-era fortune to build this sanctuary in memory of his wife.

The final resting place of President Chester A. Arthur and hundreds of others from Revolutionary War soldiers to poets, politicians, and painters.

The small burial plot is located in a mall parking lot.

This elaborate High Victorian Gothic structure is one of the world's few 16-sided buildings.

The first American home of the isolated, egalitarian religion has a trove of Shaker architecture and artifacts.

The largest museum dedicated to Italian Americans on the East Coast is located in a 100-year-old church.

This giant monument of the RCA mascot is a beloved fixture in Albany, New York.

A CT scan revealed the identity of this 3,000-year-old mummy that everyone erroneously thought was female.

Once a thriving town of 100, Argonne was abandoned around 1970.

An abandoned lighthouse located on the cliffs of Barbados.

This 16th-century pole was once used in brutal public executions.

More than 500 years after his death, a medieval ruler's remains were found buried under a parking lot.

The unique collection includes bronze cast handprints of some of America's most famous astronauts.

Believed to be haunted, this old cemetery is beautifully adorned with Spanish moss hanging from the trees.

A swamp that was the site of prehistoric water burials also managed to preserve its corpses for millennia.

A nuclear power plant abandoned along with an international allegience.

The beauty of urban decay, hiding some dark secrets.