At the centre of Xi'an is a large square flanked on one side by a bell tower and on the other by a tower containing several large drums. These were common architectural features of Ming Dynasty (1368-1644) cities: the bell would be rung to mark the dawn and the drums struck at dusk. These timekeeping practices are no longer observed, but the well-preserved bell tower, now surrounded by department stores and chaotic traffic, has become a symbol for the legacy of the ancient city.