You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Nanjing

Context:
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 the Taipings 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.

Question:
When was the Porcelain Tower destroyed?

in the 19th century