An Irish Memorial commemorating those who perished due to potato blight.

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

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

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

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

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

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

A blend of art, antiquities, and Americana fill this museum, surrounded by whimsical, enchanting gardens.

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 might just be the TARDIS of bookstores.

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