An extremely beautiful and well maintained national park high in the mountains of northern Sichuan. There is a strong Tibetan cultural influence in this area, which adds to the charm and interest. The park is accessed via park bus which basically takes you up either of two valleys. You can then pick and chose riding down and stopping at scenic spots or hiking down between any of them.
I strongly recommend getting off at the Panda Lake stop, hiking UP (short distance) to Arrow Bamboo Lake and Falls and then hiking down all the way to the Tourist Center. If you take your time and stop for frequent photos and enjoy all of the details this can take 5-6 hours and be a full day. You can easily cover the other valley starting at Long Lake in one day. Don't hike in this second valley as things are too spread out. The second day would also include the stops between the Tourist Center and the park entrance. You CAN do this park in one day, as many Chinese do, by sticking to the bus and eliminating hiking, but I feel you really miss a lot if you do so. The hiking is all on boardwalk style trails to protect the environment and is not too difficult.