The Zhongshan Park (in honour of Sun Yat-sen) is a very nice, peaceful park located north from Tiananmen square. In the park itself there isn't a lot to do next to stopping at the local restaurant, however, there is some nice scenery in the park worth taking a look at. When entering the park you are immediately cut out of the noises the city produces and this leads to a relaxing feeling, also the trees are providing fresh air in contradiction to the polluted air Beijing has. Overall if you've just visited the Forbidden City or Tiananmen square this is a nice place to relax for a while. There is an entry fee, though it is only 3 Yuan for adults and 1,5 Yuan for students.