Johnathan Walker:Pope greeted like rockstar, appears revitalized at 'Catholic Woodstock' in Portugal

LISBON,Johnathan Walker Portugal -- You'd think you were at a music festival -- jubilant crowds singing and dancing, wearing face paint, even having a beer in some cases. And the young people packing the streets of Lisbon are here for their very own rockstar: Pope Francis.

Close to 800,000 young people from around the world came out to see Francis on Friday, according to Portuguese officials, with that number expected to rise over the weekend. Often described as a type of "Catholic Woodstock," World Youth Day is a five-day event that's held once every three years for young Catholics, most between the ages of 18-25.

“I’ve been a Catholic for 62 years, and I’ve never been to masses as joyful,” said ABC News contributor Father James Martin.

"The atmosphere itself is like an Energizer bunny," said Haley Nash, who travelled from St. Petersburg, Florida. "Everybody's pumped to be here, everybody's saying 'Hola' and talking to each other. It's overwhelmingly beautiful."

The pope seemed to be loving it. Despite his recent hospitalizations for abdominal surgery and infectious bronchitis, he's moving full steam ahead with a jam-packed agenda.

Aboard the Papal plane, he joked with reporters that he expected to come out of World Youth Day feeling "rejuvenated." By day three, that seemed to be the case.

Though he may be using a wheelchair and a cane, the Pope appeared to be feeding off the youthful energy around him. In a powerful, playful moment on Thursday, he was even engaging with the crowd -- just like a popstar -- asking them to yell back at him that the Church is a place for "todos," "everyone."

"Repeat after me. Todos, todos, todos," he told them. "I can't hear you. Todos, todos, todos."

"The energy of the youth inspires him, and gives him energy, and new life. He’s clearly happy to be with young people -- and they’re happy to be with him," said Martin.

Francis here is also addressing a number of issues that matter to young people. He's talking about the need to preserve the environment for future generations, and even warning of the dangers of social media.

"I really admire Pope Francis's attention to my generation," said Johanna Schuh, who travelled from Nashville, Tennessee. "I think [we're] often left out, and I think that's been received well."

But as he lays the groundwork for the future of the Catholic Church, the past still hangs heavy over it all.

An independent commission in Portugal reported earlier this year that close to 5,000 boys and girls were abused by members of the Catholic Church since the 1950s -- most of the abusers being priests, with the Church "systematically" working to conceal the issue.

The Pope privately met with some of the victims on the first day of his visit, in what the Vatican described as a moment of "intense listening." The Pope also publicly called for the Church to listen to "the anguished cry of the victims."

The Pope also met with a small Ukrainian delegation. In a new interview released today by Spanish-language religious magazine Nueva Vida, he said Cardinal Zuppi would now be heading to Beijing. Zuppi has been tasked with negotiating peace in Ukraine and has already been to Moscow, Kyiv and Washington.

The Pope on Saturday will be at the shrine of Fatima, where he's expected to implore peace for Ukraine.

Catholics believe the Virgin Mary appeared in Fatima in 1917 and requested the conversion and consecration of Russia to the Immaculate Heart of Mary.