Christianity being an Abrahamic religion, it follows the disciples of Lord Jesus Christ. The followers of the religion believe Jesus is the saviour of humanity and is there to help the people in any
sort of problem. They believe Christ is the son of all Gods and is a Massiah to all the people to bring peace and prosperity. The people who follow Christianity celebrate many festivals, the major ones include Good Friday, Easter, and Christmas.
Good Friday:

Many people also refer this day as Black Friday, Holy Friday, and Great Friday. The Good Friday is a holiday in Christian community as this day is considered as the day when Christ was crucified and is the day of his death at Calvary. Many people keep a fast on this day and spend the time in church providing their services. In many western countries, the holiday is legal and law prohibits many activities such as horse racing, dancing or any such activity seen as profaning the solemn of the day. Christian community including Angelicin, Protestant, Lutheran, Orthodox, Methodist, Catholic, everyone gives this day immense importance. The day is considered a mourning day and hence, the clergy wear a black-vestments instead of Purple and red usual.
Easter Day:
Celebrated on the third day of crucifixion as Resurrection of Jesus Christ. Resurrection is the conception of coming back to life after death. In early days, it created a major controversy on fixing the dated of observing the rebirth of Christ in eastern and western community. The controversy is known as
Paschal controversy and it was not actually resolved until eighth century. The Asian minors and Jews consider the day od crucifixion the same, the fourteenth day of full moon in springs and the day of Resurrection, two days later to the day of crucifixion, which is the sixteenth day, Easter day. Easter has its own customs where people decorate their Easter eggs. Lenten ends their fast of three or forty days with meat, egg, ham and bread and hence, this day is celebrated as a feast.
Christmas:

Christmas is like what Diwali is to Hindus. It is celebrated as the birthday of Jesus Christ. It is believed, Jesus Christ was born in the Bethlehem in a stable. Mary was a young girl, who was about to get married to a good man, Joseph. When they were in Nazareth, an angel came to Mary and told her, she is about to have a baby, who will be called as ‘son of Gods’, and being an obedient kid of God, accepted the blessing. And hence, the concept came in, mother Mary was a virgin. They had to move to Bethlehem from Nazareth due to some issues of taxes from the roman Emperor Caesar Augustus. Mother Mary, gave birth to Lord Jesus and the news spread wide, a baby is born who is going to be saviour of humanity. Hence, Christmas is celebrated all over the world. They decorate their houses and the Christmas tree, sings Christmas carols and exchange gifts.