The first patient has been admitted to Ysbyty Calon Y Ddraig, the Dragon's Heart Hospital inside Cardiff's Principality Stadium.
It is the largest temporary hospital in Wales and the second largest in the UK and will provide up to 2,000 additional beds for Covid-19 patients.
Today, Cardiff and Vale University Health Board confirmed the hospital had received its first patient, who had been transferred there by St John Ambulance.
St John Ambulance acknowledged the moment on Twitter, writing: "We've been supporting communities in Wales for over 100 years and today marked another key moment in our history as we work together with Cardiff and Vale University Health Board supporting those who need us at the Dragon's Heart Hospital."
And the health board tweeted the following video...
The temporary hospital, which officially opened on Monday, April 20, will care for patients who are coming to the end of their treatment for Covid-19 and require rehabilitation and support, or end-of-life palliative care.
Facilities include mobile x-ray, CT scanners and care for people in the last weeks or days of their lives.
Corridors once full of fans and stewards have been replaced with nurses' stations and monitoring equipment.
Function rooms normally packed full of business people are now wards, while coveted boxes overlooking the pitch are full of hospital beds.
Where the pitch is normally found, there is one of the largest tents in Europe. The huge white structure covers the whole playing area and will be home for sick patients if hospitals can't cope.
One ward will be for patients who have had Covid-19 but can't yet go home.
