The summer palace is the old Royal retreat here in Beijing, and is a must see when here. It is located about 20 km outside the city centre, but it is defiantly worth the time to get there. It is a wast area with many building located around a lake. The biggest one is a temple on a “artificial” hill that was made there. We where not allowed to visit the temple, but you get a good glimpse from the lake shore. Another possibility is to go on one of the many boats that give you a little bit closer look.