The "spiritual Olympics" of the Catholic Church will be staged in Ireland next week, attracting thousands of pilgrims from around the world.
Final preparations are under way for the 50th International Eucharistic Congress, which will begin with an open-air Mass for 25,000 people on Sunday.
Some 230 cardinals and bishops and 12,000 priests and deacons will attend events in Dublin throughout the week of celebration.
Organisers have described Congress as an international gathering of people, with it being held in a different country every four years.
"It is a momentous occasion, it is our spiritual Olympics," said a spokeswoman.
The RDS in Dublin has been transformed into a eucharistic village for the eight-day festival of faith and culture, which will feature 223 keynote speakers and 160 workshops featuring talks, addresses, group reflections, meetings, concerts and plays.
Some 25,000 pilgrims are expected every day, with 7,000 visitors due from more than 120 different countries. Some 1,500 are travelling from Scotland, England and Wales.
Highlights include a procession which will be held on Wednesday evening, with more than 80,000 people expected at the Final Mass, Statio Orbis, at Croke Park Stadium on June 17.
The last time the event was held in Ireland was in 1932 when the Catholic Church held a firm grasp over the Irish people. Tens of thousands of people then packed the Phoenix Park for the final public Mass.
But in recent years the Catholic Church in Ireland has been rocked by several State inquiries which revealed decades of abuse and cover-ups by church hierarchy and State authorities.
Cardinal Sean Brady, head of the church in Ireland, has also dismissed several calls for his resignation over his role in a secret inquiry into a dangerous paedophile priest in 1975.
Taoiseach Enda Kenny has criticised Rome while the Irish Embassy in the Holy See had also been closed, ending Ireland's 83-year diplomatic presence in the Vatican.
The Irish Survivors of Child Abuse (Soca) plan to stage a "dignified" protest outside the RDS on Sunday to highlight its disgust at Cardinal Brady's refusal to step down as Primate of All Ireland over the recent Father Brendan Smyth scandal.
Cardinal Brady acted as a note-taker during a probe into the notorious paedophile priest and was given a list of children's names who were being abused - but failed to inform Gardai and their parents.
Spokesman John Kelly said the protest will be about the Vatican interfering with Irish sovereignty and its laws.
"The Ireland of 2012 is not the country of 1932 when fear of and deference to the Church was the norm," said Mr Kelly.
"We are a sovereign nation and resent the intrusion of foreign powers and its operatives which view themselves above our laws and immune to the common rules of humanity."
Monsignor Brendan Byrne, Diocesan Administrator of the Diocese of Kildare and Leighlin, said Congress 2012 was a hugely significant event in the life of the Church in Ireland.
Cardinal Marc Ouellet has been appointed to represent Pope Benedict at Congress 2012 and will celebrate the opening mass. The Canadian is a senior Vatican official who heads the Congregation for Bishops, which deals with the appointment of bishops around the world.
"Thousands of people from all over the world will gather in the RDS and in Croke Park, to celebrate their faith," said Monsignor Byrne.
"Many more will join in the Congress through television and the internet.
"The Congress theme - The Eucharist: Communion With Christ And With One Another - is a call to renew the traditional deep faith and trust we have in Christ's presence in the Eucharist, which has been, and continues to be, the cornerstone of our faith."