Q: Passage: On September 27, 1821 the Army of the Three Guarantees entered Mexico City, and the following day Iturbide proclaimed the independence of the Mexican Empire, as New Spain was henceforth to be called. The Treaty of Cordoba was not ratified by the Spanish Cortes. Iturbide included a special clause in the treaty that left open the possibility for a criollo monarch to be appointed by a Mexican congress if no suitable member of the European royalty would accept the Mexican crown. Half of the new government employees appointed were Iturbide's followers.

Question: Based on this passage, where did mexico win its independence from spain? Let's give stream of consciousness first:
This is the relevant information: On September 27, 1821 the Army of the Three Guarantees entered Mexico City, and the following day Iturbide proclaimed the independence of the Mexican Empire, as New Spain was henceforth to be called. Therefore, the final answer is Mexico City.