What are the holy days of obligation for the Catholic Church?

There are 10 universal holy days of obligation of the Church. However, Bishops Conferences may choose to not celebrate some of to transfer them to Sunday, with approval of the Apostolic See (Rome). The U.S. norm, if different, is indicated in parentheses.

Holy Mary Mother of God, January 1
Epiphany (U.S.: Sunday after January 1)
Ascension, Thursday 40 days after Easter (Sunday in some U.S. dioceses)
Corpus Christi, Thursday after Trinity Sunday (Sunday after Trinity)
Assumption, August 15
Saint Joseph. March 19
Apostles Saints Peter and Paul (not observed)
All Saints, November 1
Immaculate Conception, December 8
The Nativity of Our Lord Jesus Christ, December 25