The birth of Jesus Christ 2000 years ago in Bethlehem in Judea is a unique event in human history. First, there is the uniqueness of Jesus Christ Himself (God & Man). Second, there is the uniqueness of His mediation. 

Acts 4:12 there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved.

The Second Vatican Council taught the central place of Jesus Christ in man's own self-understanding. Christ reveals man to himself, He "fully reveals man to man." (Constitution on the Church in the Modern World Gaudium et spes 22). By restoring to man the divine likeness in which he was created Jesus shows all human beings what it is to be a man, a creature made in the image and likeness of God. 

Col 1:15-17 ¹⁵ He [Jesus] is the image of the invisible God, the first-born of all creation; ¹⁶ for in Him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or principalities or authorities all things were created through him and for him. ¹⁷ He is before all things, and in him all things hold together.

Furthermore, Jesus Christ is the beginning and end of creation, He from whom it came and to whom it is going.

It is sometimes said that the great monotheistic religions of Judaism, Islam and Christianity share this in common, they are religions of the Book, that great Book of books which reveals the unity of God. However, Christianity is really a religion of a Person, Jesus Christ, the God-Man who reveals God Himself. Even the Church is a Mystical Person, the mystical Christ, incarnate in the world in the Catholic Church in order to reveal Jesus Christ to every generation and to bring His salvation to the people of every time and place.