A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

The humble field where the first Major League Baseball game was played.

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

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

The first American department store, and home to the largest operating musical instrument in the world.

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

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

The taxidermied remains of Charles Dickens' pet raven, which helped inspire one of Edgar Allan Poe's most famous poems.

Huge masonic hall in Philadelphia with lavishly themed rooms.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

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

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

A rare view of a preserved Victorian science museum.

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

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

This plaque marks a place where one of Hollywood’s most famous dancers got his start.

The legacy of baseball great Roberto Clemente is preserved in a retired Pittsburgh fire station.

Sections of the iconic limestone columns have been left uncleaned as a reminder of the city's polluted past.

Once used to screen films for theater owners to rent, this historic building is now a start up hub.

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

The last street in Pittsburgh that's paved with wood.

The residents of the Neighborhood of Make-Believe live without much fanfare within the Pittsburgh Children's Museum.