Where did Juan Diego see the Virgin Mary?

In St. Ignatius' own Story as told to Luis Gonzalez de Camara (No. 24), this is what Ignatius tells us of his vision of the Humanity of Christ and of the Blessed Virgin. "Often in prayer, and even during a long space of time, did he see the humanity of Christ with the eyes of the soul. The form under which this vision appeared was that of a white body, neither large nor small; besides, there seemed to be no distinction of members in His body. This vision appeared to him often at Manresa, perhaps twenty or even forty times, once at Jerusalem, and once when he was at Padua. He saw the Blessed Virgin under the same form, without any distinction of members. These visions gave him such strength that he often thought within himself, that even though Scripture did not bear witness to these mysteries of faith, still, from what he had seen, it would be his duty to lay down his life for them."