The remains of a enormous earthen figure of unknown origins cuts across a rural Wisconsin road.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Walk over a 150 year old manhole.

The phone booths of New York City have all but disappeared, but their remains were once found in this "graveyard," sadly now removed as well.

One of the only single-person private gravesites in New York City.

Visit the monolithic tomb of America's most famous general.

Built hundreds of years ago this downtown iron barrier once protected a much despised king.

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

Possible relics of the ancient Roman city are hidden in this restaurant's façade.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Built just after the American Revolution, the oldest row house in New York City still stands in Chinatown.

Manhattan's lighthouse, erected at the insistence of the unsinkable Molly Brown.

Revolutionary War casualties fill the only 17th century structure remaining in Manhattan.

A hidden "place of interment for gentlemen."

Once thought to be the fabled Holy Grail, it is now known to be an oil lamp.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.