God works in mysterious ways, but when it comes to a Papal visit, it's a miracle of engineering.
Pope Francis needs an army of the faithful backing him up for his Ireland visit next week for the culmination of the World Meeting of Families.
The country is bracing itself for a holy show in the best possible sense.
And the advice to those travelling is: Get your jabs. Ireland's health authority has warned that large gatherings pose their own risks.
So it's highly advisable to be up-to-date with vaccinations.
More than 1,000 nurses, doctors and paramedics will be stationed in Dublin's Phoenix Park during the Papal Mass on Sunday 26 August.
Being prepared means that there will even be a mortuary, so that if anyone dies their body can be held until undertakers get to the scene.
Babies might be born too: At the last World Meeting of Families in Philadelphia 2015, six women were whisked to hospital to give birth.
The organisers are expecting a total of 500,000 people to come to Phoenix Park to see the Pope.
By comparison, the 1916 Centenary Easter Sunday Parade in Dublin in 2016 was attended by 350,000 people.
But it's not quite the estimated 1.25m who were in Phoenix Park to see Pope John Paul II in 1979, the last Papal visit to Ireland.
MCD productions, the team behind Pope Francis' Phoenix Park Mass, has staged concerts for Beyonce, Westlife, Coldplay and U2.
Designers Arcana have been engaged to create the perfect stage. On hand will be Arcana's Johnny Donnelly, formerly of the Saw Doctors.
In operational terms, the Phoenix Park faithful will be more than relieved to know that there will be 2,500 toilets available and 20,000 directional signs - as well as 5,000 traffic cones marking neighbouring streets.
More than 4,000 Communion servers will be deployed for the Mass, each responsible for one or more "corrals" of 1,000 people into which the expected crowd of 500,000 will be organised.
The goal is to be able to ensure that everyone who wants Communion will get it within 20 minutes.
Roughly 2,500 extra train runs are being planned by Irish Rail in order to move the throngs of pilgrims expected to descend on the Pope's public events.
On Sunday, 2,500 police will be on duty, including 700 at Phoenix Park for the Papal Mass.
Time for tea
As the Irish can go nowhere without a cup of tea, there will be 150 food and drink outlets in Phoenix Park.
In the spirit of Mrs Doyle of Father Ted fame: "You will, you will, you will." And they will.
Organisers have worked out that if just half of the people at the event have a cuppa, 31,250 litres of milk will be used.
They also estimate that about 25,000 sliced pan loaves will be used for sandwiches.
The overall cost of the Pope's visit is being estimated at about 35m euros (£31m).
Of that, 22m euros is being raised by the Catholic Church in Ireland and the remainder from the Irish government.
This is a green visit - Pope Francis will be wearing green and those who attend are being asked to think green.
A strict "leave no trace" policy will be in place - and green bags will be given out so visitors can collect all their rubbish to take home.
The tills are ringing across Ireland as Pope memorabilia hits the shop shelves.
You can buy Pope T-shirts, mugs, fridge magnets, bunting, flags and umbrellas.
There is even a lollipop - or lollipope - and a collapsible cardboard chair featuring the pontiff, which is, its makers reassure, fully biodegradable.
You can also buy an Irish-dancing Pope Francis waving a Guinness, as well as a solar powered one who can swivel his hips.
Meanwhile behind the scenes, there is the pressing matter of priests' vestments.
Volunteers have been working to iron the robes to be worn by priests taking part in the Mass.
A call went out for people happy to do a day's ironing for free - they just need to bring their own iron and board.
No reward is offered for the work... that, presumably, will be in Heaven.
Papal visit to Ireland: Itinerary highlights
Saturday 25 August
- 08:15 - Departure by plane from Rome for Dublin
- 10:30 - Arrival at Dublin Airport for official welcome
- 10:45 - Transfer to Áras an Uachtaráin (Irish president's residence)
- 11:15 - Welcome ceremony with President Michael D. Higgins
- 12:10 - Arrival at Dublin Castle for meeting with authorities, civil society and diplomatic corps
- 15:30 - Visit to St Mary's Pro-Cathedral
- 16:30 - Private visit to the Capuchin Day Centre, a centre for homeless people
- 19:45 - Preside at the Festival of Families at Croke Park stadium
Sunday, 26 August
- 08:40 - Departure by plane for Knock
- 09:45 - Arrival at Knock Shrine for visit to the Apparition Chapel and recitation of the Angelus
- 11:15 - Departure by plane for Dublin
- 12:30 - Lunch with the Papal Delegation
- 15:00 - Closing Papal Mass of the World Meeting of Families in Phoenix Park followed by a meeting with the Irish bishops
- 18:30 - Farewell ceremony at Dublin Airport
- 18:45 - Departure by plane for Rome
- 23:00 - Arrival in Rome