The United States Capitol's former columns still stand.

The "Seinfeld" diner.

A plaque immortalizes the spot where the early American spy said his famous last words: "I only regret that I have but one life to lose for my country."

The body of St. John Neumann and his collection of hundreds of relics, on display in a Philly church.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

The oldest surviving botanic garden in the United States.

Pennsylvanian mass grave and possibly mass murder.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

This Philly cemetery is the eternal home of many famous area residents, including Rocky Balboa's wife.

This might just be the TARDIS of bookstores.

Where America's first doomsday cult awaited the end of the world.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

A layered tribute to the work of mosaicist Isaiah Zagar.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

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

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Called the "Armenian Stonehenge," this ring of menhirs pierced with holes may be a prehistoric astronomical observatory.

Despite producing just a handful of movies, a brave and lyrical filmmaker has an entire museum dedicated to him.

This series of Armenian caves held the oldest brain, shoe, and winery in the world.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

Nestled in a peaceful valley, this Armenian monastery may have been saved from Mongols thanks to the eyes of God.

Giant stone letters dedicated to the founder of Armenia's alphabet.