Wissahickon Valley Park runs seven miles from Chestnut Hill through Mount Airy and eventually south to Manayunk. It encompasses 1,400 acres and is part of Philadelphia's park system. It features hiking trails including Forbidden Drive, a 5.42-mile, car-free path that runs throughout the park. There is an additional 50 miles of trails throughout the valley. There are various landmarks—mansions, stables and a monastery, to name just a few—throughout the area. A group called the Friends of the Wissahickon works to preserve the park.