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

Site of a famous 19th-century transcendentalist utopian community, now abandoned.

This factory made "health corsets" that were a step towards liberating women's bodies.

An abandoned asylum once on the cutting edge of lobotomies may be reborn as a Christian college.

This Detroit ruin was once a gothic bastion of its community, but now it stands as a haunting ruin.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

A century-old network of freight tunnels underneath the city's historic business district.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Abandoned since the 1950s, the streetcar lane beneath the heavily trafficked bridge lays empty and unused.

The abandoned bathhouse is all that remains of the hot springs considered Florida's original tourist attraction.

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

This abandoned school has had many lives since the early 1900s, and all of them doomed.

An abandoned theme park with a strange and tumultuous past.

Along the historic Mother Road is an old gas station with a secret counterfeiting past.

Ruins of the elaborate house where the enigmatic costume designer threw glamorous parties for New York's theatrical elite.

The old Route 66 town straddling Texas and New Mexico died along with the Main Street of America.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.

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

The ruins of a 19th century shelter run by the Independent Order of Odd Fellows.

An abandoned boat that's been stranded mysteriously for decades.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

One of the world's largest automobile junkyards is a unique landscape of metal and moss.

Once the world's largest reinforced concrete structure, this abandoned bridge now beckons urban explorers.

An abandoned, decaying sculpture garden built by an eccentric physician in the 1920s now looks more like a forgotten cemetery.