The St. Joseph Center was inaugurated in June and features a number of small astro-turfed fields, a tennis court and an above-ground pool thanks to funding from benefactors who met the pope July 18 at his residence, the Domus Sanctae Marthae, the Vatican said.

After meeting about two dozen of the donors, the pope went by car to the outdoor sports center located above the Vatican Museums to greet the children and volunteers. In past years, the summer program for children aged 5-13 had been held inside the Vatican's Paul VI hall.

The pope answered a few questions from the children, such as, who his heroes were when he was little. "My parents," the pope said, according to Vatican News.

Pope Francis shared some memories of growing up with his four siblings in Argentina, including spending summers with his paternal and maternal grandparents.

"Talk to your grandparents" and be close to them, the pope told the children. "Grandparents help us find our way."

He also encouraged the children to always be peacemakers, saying "making peace is the most beautiful thing in life and we have to learn to make peace at home when we argue with siblings, when we get mad."

"Never go to bed without making peace," he said. "Never go to bed with 'the spirit of war.'"

When asked how they could best prepare for the Jubilee Year 2025, the pope told them to prepare with joy since the term "jubilee" is related to a word meaning "rejoicing."

The children prayed with the pope and then released about 300 biodegradable balloons filled with helium and a written message saying, “To you dear child: you are precious in the eyes of God."

The organizers said they wanted to share these words from the pope with as many people as possible, Vatican News reported.