This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

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

This park contains a number of standing stones meant to heal and inspire.

An ideal wedding spot that is almost too ideal.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

This abandoned Poconos resort is haunted by a history of kitschy romance and a violent fugitive.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

An Industrial Revolution-era public work that purified water using nothing but sand.

The towering figures were created from the cemetery's fallen old-growth trees.

The United States Capitol's former columns still stand.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

A historic covered bridge is but one example of an oddly prevalent American urban legend.

Mysterious rocks that ring musically when struck.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

This jail which was in service for over a century is now open for curious visitors.

The wooded estate of the Forest Service employee responsible for D.C.’s cherry blossom trees.

A benevolent, 16-foot-tall river dragon lives on a suburban lawn.