Parishioners celebrate birth of Jesus at Mass in Milwaukee, New York, the Vatican

MILWAUKEE -- Church services are a big part of the Christmas Eve and Christmas Day celebrations for many families.

At the Cathedral of St. John the Evangelist Sunday, December 25th, Mass began at 9:00 a.m.

Catholic churches are typically decorated with the nativity scene, welcoming baby Jesus -- celebrating his birth.

Cathedral of St. John the Evangelist

Christmas is one of the most important days of the church year -- second only to Easter. It is the feast of the incarnation -- the day Jesus was born.

Jill Olen said Mass offered a chance to teach her children the reason for the season.

"The presents are about the birth of Jesus, and without him, we wouldn`t have the presents and we wouldn`t have the Lord`s forgiveness or a lot of things -- so it`s all about Jesus today and that`s what we`re trying to tell them and teach them," Olen said.

Hundreds gathered at St. Patrick's Cathedral in New York Sunday to take part in Cardinal Timothy Dolan's Christmas Eve Midnight Mass.

Cardinal Timothy Dolan

This year, a Plexiglas sliding door was installed in the back of the cathedral so more people could watch the services from outside as well.

Cardinal Dolan urged parishioners not to lose hope as he touched upon the significance of Hanukkah and Christmas Eve falling on the same night.

"He has bent down to save us from our big mess. The people in darkness see a great light -- Isaiah the prophet tells us," Cardinal Dolan said.

This was the fourth time in 100 years that the start of Hanukkah fell on Christmas Eve.

Cardinal Dolan said Christmas and the Festival of Lights symbolized the victory of light over darkness.

Meanwhile, Pope Francis wished for people who have been scarred by wars to have peace on Christmas.

At St. Peter's Basilica, the Pontiff talked about those who have suffered through Syria's civil war, specifically those experiencing "the most awful battles" in Aleppo.

Pope Francis

He called on the international community to find a solution to end the war.

Ahead of Christmas, thousands of civilians were evacuated from Aleppo -- leaving behind their homes in snowstorms and sub-zero temperatures.