The architecture of the Benjamin Franklin bridge is stunning along with many other bridges found around this area or in New York. Definitely grab a camera and tripod and create a long exposure photograph of this bridge.
Apart from Penn's Landing being a cool place for tourism or to hang out and visit, it's also quite a nice place to photograph. I've gotten the chance to take some shots while my friends were bugging me to leave, but it's still a must go to place for photographers no matter their skill level. Make sure to have a tripod in hand, and, if needed, a shutter release button. Other than that, become creative with it! There's many areas to snap a great photograph of the bridge, and trust me, it'll be rewarding for sure.
Just a tip, the longer the exposure the more silky the water effect will become, just make sure to look at the balance meter not to overexpose the picture. (I shoot landscapes like this with a 30 second shutter and an F-Stop of 11 or higher).
Next time you're around Penn's Landing keep this in mind and you'll be able to grab a impressive picture.