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

A daily replay of the experiment that proved the rotation of the Earth.

A field of nothing but boulders which resembles a giant's gravel driveway.

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

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

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

This hidden gem of a garden has one of the only surviving Victorian ferneries in America.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

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

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

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.

The oldest surviving botanic garden in the United States.

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

This might just be the TARDIS of bookstores.

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

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

A rare view of a preserved Victorian science museum.

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

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.

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