16 Solemnities in the Catholic Church:

    - January:
            - 1, Octave of Christmas - SOLEMNITY OF MARY, MOTHER OF GOD
            - 6- EPIPHANY, the three Kings
    - March: 
            - 19, JOSEPH, HUSBAND OF MARY
            - 25, ANNUNCIATION
    - March to June:
            - EASTER - the Solemnity of Solemnities... see Moveable Feasts
            - ASCENSION Day - 40 days after Easter, Ascension of Jesus
            - PENTECOST - 50 days after Easter, Pentecost, the Holy Spirit
            - HOLY TRINITY: First Sunday after Pentecost, The Most Holy Trinity
            - CORPUS CHRISTI: Thursday after Holy Trinity, in USA celebrated the next Sunday, Eucharist
            - SACRED HEART: Friday following the Second Sunday after Pentecost, Sacred Heart of Jesus, Saint Margaret - Divine Mercy, Sister Saint Faustina 
    - June:
            - 24, BIRTH OF JOHN THE BAPTIST
            - 29, PETER AND PAUL, APOSTLES
    - August:
            - 15: ASSUMPTION OF MARY
    - November:
            - 1, ALL SAINTS
            - 2, ALL SOULS, between Feast and Solemnity
            - CHRIST THE KING, Last Sunday in Ordinary Time:
    - December:
            - 8, IMMACULATE CONCEPTION
            - 25, CHRISTMAS

Moveable feasts in Christianity:

• Baptism of the Lord, the Sunday after January 6
• Mardi Gras - 47 days before Easter, the Tuesday before Ash Wednesday
• Ash Wednesday - 46 days before Easter, the Wednesday starting Lent
• Lent - From Ash Wednesday to Easter
• Holy Week - From Palm Sunday to Easter
• Palm Sunday - Sunday before Easter
• Holy Thursday - Thursday before Easter
• Good Friday- Friday before Easter
• Easter - the date around which the other Solemnities and Feasts are placed, the Solemnity of Solemnities.
• Divine Mercy, Sister Saint Faustina, Sunday after Easter
• Ascension Day - 40 days after Easter
• Pentecost - 50 days after Easter
• Corpus Christi - 60 days after Easter
• The Sacred Heart of Jesus, the Friday after the second Sunday after Pentecost - Sacred Heart of Jesus, Saint Margaret - Divine Mercy, Sister Saint Faustina 
• Immaculate Heart of Mary, the day following the Feast of the Sacred Heart of Jesus. That is the Saturday after the second Sunday after Pentecost.
• Advent - Four weeks before Christmas
• feast days of some significant saints days, if a movable feast falls too close to their usual date.

Fixed feasts in Christianity:

• January 1: The Solemnity of Mary, Mother of God
• January 3: Most Holy Name of Jesus
• January 6: Solemnity of the Epiphany
• Presentation of Christ in the Temple - February 2
• Transfiguration - August 6
• Assumption of Mary/Dormition of the Theotokos - August 15
• Exaltation of the Cross - September 15
• Christmas - December 25