On the nearly entirely flat 8.4 mile paved recreational path around the Schuylkill River. The entire course is entirely traffic free, save one onramp crossing by the Philadelphia Art Museum. The course passes many historic sites including the Rocky Statue and the "Rocky" steps in front of the Art Museum, Laurel Hill Cemetery, and Boathouse Row.
parking is free on Sedgley Avenue, across from Lloyd Hall, and up it into Fairmount Park. There are also paid lots within walking distance that you can Google.