MORE: Vatican's Canonization Booklet (pdf)
The Via della Conciliazione, the main boulevard between Rome and Vatican City, is normally filled with cars, busses and taxis, but not Saturday. The police have closed it off to vehicle traffic and the people are taking it over in preparation for the historic day Sunday.
It is a festive atmosphere of Catholic faith and ethnic pride, and Poland is well-represented, along with Chicago's Polish Americans.
Krzysztof and Margaret Bis and are there from suburban Orland Park, and it's all about John Paul.
"This kind of occasion in history is never going to be happening again for us," Krzysztof Bis said.
"I want to pray, you know, with all people here," said Margaret Bis.
Throughout this city, there's growing anticipation for the coming major event: Increased police presence, temporary medical facilities, pallets of bottled water for the thirsty crowds, and in the popular tourist destination of Piazza Navona, a giant screen television to provide an alternative viewing location of the canonization mass.
That's where seminarian Paul Solomon from suburban Wheaton plans to be. He's seen first-hand how the foundation laid by two former popes has led to the popularity of the current Pope Francis.
"Even talking with friends back home who aren't catholic, they're very excited with the way Francis is living his papacy," he said.
Not everyone, however, is approving of Pope John Paul becoming a saint. A group representing clergy sexual abuse victims is here in opposition.
"Thousands of children lost their innocence under pope John Paul II's regime and we don't believe that's saintly behavior," said Barbara Blaine, SNAP Survivors Network.
Catholic experts argue that sainthood is not proof of a perfect life, but a life lived close to god as an example of holiness.
Elsewhere in Rome, Chicagoans are celebrating the life of John Paul II. A group of Chicago Polish-Americans held mass at St. Stanislav Church.
"He's a father figure to all of us, and so we appreciate it and he's our role model and we look up to him," said Aux. Bishop Andrew Wypych, Archdiocese of Chicago.
"I'm very, very happy to be born in Poland and to be living in Chicago. It's very emotional for us," said Zofia Cygan of Naperville.
A spiritual pilgrimage for these Chicagoans celebrating mass, each with an individual story of why they believe they must be here now.
"It means the world to me, because John Paul II was so close to us spiritually and he was such a great leader, spiritual leader, so we're just thrilled to be here," said Donna Nowobilski from Lemont.
Henry Kosecki survived a Nazi concentration camp at the age of 10, eventually freed toward the end of World War II.
"I never thought I would ever live that I would see Polish Pope, here in Rome so, we were so excited," he said.
Rabbi Jay Rosenbaum, a special invited guest who's worked with Pope Francis on Catholic-Jewish relations, and has witnessed the positive changes through the leadership years of the popes who will be saints.
"People never thought that they'd live to see it, it's a sense of embracing one another knowing what brings each other joy and pain and a profound sense of respect," Rabbi Rosenbaum said.
The canonizations will actually occur at the beginning of the mass Sunday and when each former pope is named: John 23rd and John Paul II. A massive cheer and ovation from the crowd is expected.
