It's an exquisite piece of history that's been off limits to the public for centuries.
Constructed in 1782, Solitude was later acquired by the city and has since become home to some reported paranormal activity.
But now, zoo guests could get the chance for a private tour - if they're able to solve a thrilling scavenger hunt called "Zoo Done It?"
Ahead of the event, Action News reporter Christie Ileto got a tour of the spirited space. Watch her full report in the player above.
For more information, visit PhiladelphiaZoo.org.