From The Manila Bulletin:
Devotees of the Blessed Mother will offer special prayers and novenas, light candles, offer flowers, and recite the holy rosary Thursday, November 21, in observance of the Feast of the Presentation of the Blessed Virgin Mary in the Temple of Jerusalem, which is believed to be the beginning of the preparation for Mary’s mission and destiny as the Mother of Jesus Christ.
The Marian feast coincides with the observance of ‘Pro Orantibus’ Day, which means ‘For those who pray.’ According to stories, Saints Joachim and Ann, the parents of the Blessed Mother, offered Mary at the young age of three, to God in thanksgiving and to consecrate her to the Lord as promised. Mary remained in the temple serving and helping the priests until her engagement to Joseph.