Two New York rooftops are home to the largest rooftop soil farms in the world.

A hands-on traveling collection of the innovative devices of yesteryear.

Plot your trip through the city on the sidewalk.

Once the tallest building in the world and the site of “the highest dinner ever held in New York” this building now holds the most expensive penthouse in the city.

Visit the site of a subway powered by nothing more than air--and lots of it.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

A modern zoetrope on the New York City subway.

Tucked in a nondescript downtown Brooklyn mall is a bar containing a remarkable turn of the century anatomical wax collection last seen in 1920s Berlin.

Walk into the 19th century without leaving Brooklyn.

Haven for steampunks.

An 1883 schoolhouse now home to collective of artists.

Memorial built in 1922 in remembrance of WWI casualties.

Step inside Lucy, the world's largest "elephant."

Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

A museum dedicated to the strange and extravagant costumes and memorabilia of the mummers, a tradition older than Philadelphia itself.

Pennsylvanian mass grave and possibly mass murder.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.

A failed piece of Orientalism has become the proud symbol of a community.

This university transit system is a 1970's vision of the future.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

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

Meet your friends, marry your true love, or tell your enemies to kiss your butt under this historic Pittsburgh timepiece.

Color-coded signs direct drivers on a network of routes designed to avoid Pittsburgh traffic.