Reference

Holy Days of Obligation are specific days in the Liturgical Year when Catholics are required to attend Mass. While the exact list can vary based on decisions by bishops' conferences in different regions, several universal Holy Days of Obligation recognized by the Catholic Church globally include:

1. Sundays: Every Sunday is considered a Holy Day of Obligation because it is the day of the Resurrection.
2. Christmas: December 25, celebrating the Nativity of Jesus.
3. Ascension: Forty days after Easter, commemorating Jesus' ascent into heaven.
4. Assumption of the Blessed Virgin Mary: August 15, honoring the assumption of Mary into Heaven.
5. Solemnity of Mary, Mother of God: January 1, dedicated to Mary as the Mother of Jesus.
6. All Saints' Day: November 1, in recognition of all the saints, known and unknown.

These are generally observed universally, but variations can occur. For instance, some countries might have additional days considered obligatory, such as the Feast of St. Patrick in Ireland or Our Lady of Guadalupe in Mexico. Additionally, some regions might transfer these obligations to Sunday if they fall on a Saturday or Monday to facilitate observance.

For more details about the days recognized in specific regions, you can check local diocesan announcements or this resource.