Toxic waste disaster that founded the Superfund program.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

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

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

This abandoned ironworks was once the most important military supplier in America.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

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

Reforestation in action is the main attraction in this abandoned quarry.

This former theme park in New York's Adirondack Mountains fell into ruin before being resurrected as a state-run campground

A deteriorating 1990s Girl Scout camp in a beautiful lush park on Lake Ontario.

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

An abandoned asylum where patients have been forgotten but their possessions remain.

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

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

The remains of what was once the world's steepest passenger funicular.

A 19th century hat factory still stands as a crumbling ruin in upstate New York.

This once sprawling resort now sits abandoned, filled with graffiti and vibrant colors from an era long passed.

A beautiful, historic location open to the public.

Once a thriving business district, this former shopping area is now an urban ghost town in the heart of the city.

Ship skeletons haunt Baltimore's waterways.

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

A castle inspired by medieval architecture is hidden in the woods of Connecticut.

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

A few stone foundations and an old graveyard are all that is left of this once thriving settlement in the wilds of Connecticut.