All of Chicago's wood-paved streets are long gone but two alleys remain.

A hollow cement depiction of time's inexorable effect on the human body.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

Industrial ruin decimated this tiny New England company town in a fashion no one saw coming… and even fewer remember today.

A beautiful, creepy 19th-century castle stands incongruous in rural Vermont.

Forgotten under the construction of a new urban roadway is a small, abandoned part of town.

Ruins of a historic medical facility sits eerily by the water.

An abandoned Depression-era zoo hidden just off the highway.

This "thrice-cursed" island is allegedly home to Captain Kidd's lost treasure.

The kind of mixed-up place that drives archaeologists crazy.

A six-story treehouse offers spectacular views of New York's Finger Lakes region.

The private island of Yale's elite Skull & Bones society is kind of a dump.

The oldest continuously operating farm in New York State.

A historic recreation of the golden age of the Erie Canal, abandoned for some time, slowly being restored.

A fictional town that was briefly brought to life before fading once again out of existence.

This dilapidated castle-like structure overlooks the Hudson River at one of its widest points and was once home to nuns.

This stone gatehouse was once the entrance to a historic mountain resort, and it had a cameo in a cheesy cult horror movie.

The abandoned grounds and derelict greenhouses of this once-magnificent Edwardian estate are now a nature preserve open for exploration.

This abandoned factory on the Hudson River once churned out a million bricks a week.

An abandoned Gold Coast-era mansion once intended for the exiled ruler of Albania, who never arrived.

This natural rock "church" might not be a proper chapel but that doesn't mean it's not beautiful.

A castle built for love, and abandoned due to heartbreak.

This old cement mine has been used as everything from a mushroom farm to a recording studio.