This is part of what was once a much larger area that contained the Emporer Qianlong's summer palace. The palace was destroyed by the British in the 1800's and that site is now called Yuan Ming Yuan. This site also was damaged but the crazy Empress Dowager Cixi had a great deal of it rebuilt and even added new structures.

The lake in this picture is man-made and is huge. The tower and the building behind it are both temples. The park itself is very large and many people come here regularly to stroll around and just generally relax.