The Pope has urged young people to “download a heart” and to use the Gospel as a “satnav for you on the highways of life”.
Pope Francis used the modern metaphors during mass for than 1.5 million young pilgrims who gathered in a vast meadow near Krakow.
Even the music was given a makeover aimed at the younger audience – the hymns were accompanied by a dance music beat.
Hundreds of thousands of people camped out overnight in the field 13 miles from the Polish city ahead of the World Youth Day event.
They turned up at the site the night before with folding chairs, sleeping bags, umbrellas and sun-hats.
Francis waved to the crowds as he toured the site in his popemobile at the start of a ceremony on Sunday morning.
Police said “over 1.5 million” people attended the event.
On his way to the site, the Pope made a stop to bless two buildings run by the Catholic charity Caritas – one was built as a day centre for the elderly and the other is a storehouse for food for the needy.
As he left the storehouse, he tried some dark bread offered by women in traditional Polish costumes and nodded in approval.
The five-day visit – his first trip to eastern Europe – is drawing to a close.
He arrived on Wednesday and has visited Auschwitz, celebrated public masses, and held meetings with young people who have travelled from around the globe to see him.
There has been tight security around the Pontiff following a series of attacks in western Europe, including the killing of an elderly priest in France.
Police said no major security incidents have been reported during Francis’ five-day visit to Poland.
On Saturday the Pope prayed for God to rid the world of the “devastating wave of terrorism”.
The medieval centre of Krakow has been overrun all week by flag-waving groups from China to Samoa and Mexico, who were entertained between masses with concerts, break-dancing and football matches.
In a message to the world’s young, he said it was up to them to fight xenophobia and “teach us how to live in diversity, in dialogue, to experience multiculturalism not as a threat, but an opportunity”.
