The oldest farmer's market in America is so ancient it was approved by the King of England.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

Dr Barnes' $25 billion private collection of art and arboretum.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

In which a local geological marvel becomes a quaint roadside attraction.

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.

One artist's love letter to his city and its citizens plays out across dozens of bright murals painted on the sides of decrepit buildings.

The oldest surviving botanic garden in the United States.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

This permanent exhibition celebrates the finest of our heartless automatons both real and fictional.

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

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

A toxic ghost town sitting atop a massive coal fire.

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

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

A museum dedicated to the former country.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

A striking symbol of the Bulgarian capital.

Bronzes and busts that once stood in the city's main squares are now relegated to a small hidden courtyard.

Hundreds of thousands of concrete bunkers crowd Albania long after the fall of Communism.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'