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:
Pope_John_XXIII

Context:
On 11 October 1962, the first session of the Second Vatican Council was held in the Vatican. He gave the Gaudet Mater Ecclesia speech, which served as the opening address for the council. The day was basically electing members for several council commissions that would work on the issues presented in the council. On that same night following the conclusion of the first session, the people in Saint Peter's Square chanted and yelled with the sole objective of getting John XXIII to appear at the window to address them.

Question:
Where was the first session of the Second Vatican Council held?

in the Vatican