Why do we celebrate Christ the King?

The Feast of Christ the King, also called ‘Solemnity of Our Lord Jesus Christ, King of the Universe,’ is a festival celebrated in the Roman Catholic Church in honor of Jesus Christ as Lord over all creation. Essentially, it is a magnification of the Feast of the Ascension established by Pope Pius XI in 1925

The Solemnity is celebrated on the final Sunday of Ordinary Time, the Sunday before Advent. This year, the feast falls on November 21, 2021.

Novena Starting November 12:

https://www.usccb.org/religious-liberty/christ-king-2021-novena