This distinctive tower is a historic reminder of how stargazing was conducted before telescopes were invented. Built in 1442, during the Ming Dynasty, and later expanded in the Qing Dynasty, this observatory is among the world's oldest. Several of the huge original bronze instruments are up on the roof of the tower, while others, including sundials, can be found on the expansive observatory grounds. The astronomical devices are beautifully embellished with clouds, dragons, and other mythical creatures. Inside the quiet exhibition rooms, don't miss the impressive replica of a gold-foil map of the constellations used during the Ming Dynasty. This museum is a pleasant spot to spend an hour or two.