As Joe Marler alluded to while announcing his retirement Last week, international rugby can be a “dream bubble”.

But towards the end of last month, when the Ireland team gathered in Portugal and began to look ahead to Friday’s rematch with the All Blacks, they were served a strong dose of reality.

The Irish team has had several guests in recent years, from Bono to Shane Lowry. Hearing from personalities outside the rugby test grind can be enlightening and light, a welcome break from training and meetings.

But perhaps no visit has awakened their souls quite like Nando Parrado’s.

Parrado was once a rugby player, but is better known as a central figure in a story both inspiring and disturbing, one that exemplifies the strength of the human spirit in the face of the greatest adversity.

In October 1972, a plane carrying members and family from the Uruguayan Old Christians Club crashed in the Andes en route to Chile.

It was a terrible tragedy. Twenty-nine of the 45 people on board – including Parrado’s mother and sister – lost their lives. Those who survived were forced to eat those who died in the crash.