Zifeng Tower (紫峰大厦) is a 450-metre supertall skyscraper in the Gulou district, completed in 2010 and for some years the tallest building in China outside Shanghai and Hong Kong. The tower has an observation deck on the upper floors with views across the city — on clear days you can see the Yangtze River, Purple Mountain, and the old city wall from above.
The tower is the centrepiece of Nanjing's central business district and represents the city's economic ambition plainly. As architecture it is unremarkable by skyscraper standards, but the view from the observation deck is the best high-level perspective over the city, combining the old (the walls, the mountain) with the new (the sprawling modern city).