At the heart of the Roman Catholic faith is Mass, a religious ceremony that connects the faithful to God and gives them strength to follow the teachings of the Christian bible.
Whether in a tiny village church in Africa or the great basilica of St Peters in Rome, this central act of worship follows ancient rituals, known as the liturgy.
It will be the same at Zayed Sports City when Pope Francis conducts Mass for a predicted 135,000. Despite the unusual setting, this will be a familiar ceremony for both the pope and his flock.
Catholics believe that in the final stages of Mass, Jesus Christ becomes present in a cup of wine and a wafer of bread that represents his body and blood. This is known as the Eucharist, a word that originates from the Greek for “thanks.”
Well before then, the congregation will have taken their places at the stadium, at the centre of which will be a temporary altar from which Pope Francis will conduct the Mass.
In churches, there are dishes containing holy water, that is water that has been blessed by a priest for spiritual cleansing and as a reminder of baptism.
At the stadium, holy water will be provided in other ways, but the ritual is the same, dipping the right hand in the water and making the sign of the cross across the chest.
When Pope Francis arrives at the stadium he will head in a procession to the altar, as the congregation stands as hymns are sung. A white cloth will cover the altar, on which stands a crucifix or cross.
Pope Francis will then kiss the altar and begin the Mass by making the sign of the cross along with a short prayer that reminds the congregation that they are under the protection of God.
This “Introductory Rite” is the first of four parts of the ceremony, and concludes with a silence for those present to reflect on their conduct and to repent for things they have done wrong. Pope Francis has said this moment is very important and should not be rushed in the service.
The second stage, the Liturgy of the Word, is devoted to story telling, beginning with a story from the Old Testament in the Bible, then one from the life of Jesus. The Pope will then give his sermon. While the formal elements of the service are conducted in Latin, the official language of the Vatican is Italian.
To reflect the diversity of the Roman Catholic community in the UAE, the Pope may use a variety of languages during his sermon.
This second part concludes with the Creed, a statement of faith by the congregation, followed by a universal prayer that often makes references to issues relevant to the region, like ending conflict.
Now comes the Eucharist, beginning with a long prayer during which the congregation kneels if possible, or bends their heads. Pieces of unleavened bread, that is made without yeast, and a cup of wine mixed with a little wine have already been placed on the altar.
The purpose of this section of the Mass, the core of the ceremony, is for the congregation to offer themselves to God. It includes a prayer in which the Pope speaks and the congregation responds.
During this part of the service, Catholics believe Jesus enters the sacramental bread and wine, representing his body and blood. Wafers of bread, known as the host, are taken into the mouths of the congregation, while the wine is generally taken only by priests at the altar.
The final part in a ceremony which often lasts up to 90 minutes, is brief. The congregation will stand for a final prayer and blessing by the Pope, who will then leave, perhaps with a final drive round the stadium before heading to the airport.