Besides the city wall, other famous Ming-era structures in the city included the famous Ming Xiaoling Mausoleum and Porcelain Tower, although the latter was destroyed by <answer>the Taipings</answer> in the 19th century either in order to prevent a hostile faction from using it to observe and shell the city or from superstitious fear of its geomantic properties.
Who decimated the Porcelain Tower?
the Taipings