Question: In 1531 an Aztec Indian named Juan Diego reported encountering a beuatiful woman surrounded by a bright light who called herself "Mary the Virgin". In presenting the information and experience to the local Bishop, a great miracle occurred. What was that miracle?
Answer: Juan Diego was instructed to return to the Bishop with his cloak full of flowers, which had bloomed out of season. When he presented them to the Bishop, the flowers fell to the ground, but an image of the Blessed Mother remained on the cloak.
Read more:
http://www.americancatholic.org/News/JuanDiego/
http://www.catholic.org/saints/saint.php?saint_id=73