This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

World's first "penitentiary," meant to be humane, drove men insane.

A stone arch leads to a cavernous 1930s spring house tucked away in the Pennsylvania woods.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The first memorial dedicated solely to the Black troops who fought for the Union.

An overlooked memorial honoring the local Washington residents who died in World War I.

Look closely and you’ll notice that the color changes a third of the way up the tower.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

This restaurant has been a haven for D.C.'s LGBTQ community since the 1950s.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Prison made famous by The Shawshank Redemption has been out of commission since 1990.

The home made famous by the 1983 holiday classic is now a perfectly preserved shrine to the movie.

Rare recess caves fill this unbelievably beautiful Ohio park.

Largest display of Wesleyana anywhere in the world.

The world's largest set of the ten commandments lay nestled in the heart of the Great Smoky Mountains.

A mailbox that saved a nature reserve.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A popular European tradition makes its way to the states on one of America's most famous bridges.

A natural gas leak provides a flickering flame beneath a waterfall.