Pope Francis officially opened the Jubilee Year of Mercy in December 2015 and Catholics have been flooding into Rome to celebrate and take part in pilgrimage.
Opening the year, the pope said: "I have decided to announce an Extraordinary Jubilee which has at its centre the mercy of God.
"It will be a Holy Year of Mercy.
"We want to live in the light of the word of the Lord: "Be merciful, even as your Father is merciful" (cf. Lk 6:36). And this especially applies to confessors! So much mercy!"
The special year is intended to show a more merciful side of the Catholic Church and the event saw a huge open air Mass at the Vatican attended by 50,000 people.
The Vatican has said it usually has around five million visitors a year, so far 13 million people have passed through the Holy Door at St Peter's Basilica.
Peter Williams from Catholic Voices told Premier why this pilgrimage is so important to Catholics.
He told Premier what happens in Catholic theology: "You go there [to Rome] in order to gain an indulgence, which is a remission of the temporal punishment of your sins (you can ask on behalf of yourself or others to be forgiven) - which you can offer up for other people as well.
"So that's an important part of Catholic spirituality, so it's no surprise not only are so many people going to Rome, but several times the usual number of people are going to Rome - that's rather wonderful."
He went on: "Rome really signifies for us the unity of the Church, the truth that comes only through God."
The Jubilee Year will end on November 20th 2016.
Peter Williams said that pilgrims will feel a sense of awe when they pass through the Holy Doors, "the awesome grace and mercy that is offered through the sacrifice of our Lord Jesus Christ, that through him and only though him we have justification before God, that we can be in that state of the wonderful relationship with God.
"So a devout person will go through that door with that very much in mind."
Listen to Premier's Hannah Tooley speak to Peter Williams here: