PHILADELPHIA -- Chartered in 1859, the Philadelphia Zoo is America's First Zoo.
It was designed to be a place where Philadelphians could come and appreciate wildlife from all over the world. But it has a spooky secret: it's believed to be haunted.
On the Zoo grounds is a building known as The Solitude.
The Solitude was built before the zoo's inception in 1784 for John Penn, William Penn's grandson, as a way to escape the hustle and bustle of the city.
Today, many zoo staff have reported seeing apparitions, the sound of music playing in the cryptoporticus, and a light in the attic that likes to turn itself on.
Other buildings on the grounds that have suspected paranormal activity are the Penrose Laboratory, The Shelly Building, and the Treehouse.