It was late afternoon when John Paul II arrived at Grant Park, a magnificent setting framed by Chicago's skyscrapers facing Lake Michigan, and another great crowd was waiting to greet him. Some people had begun arriving in the near-freezing temperatures early this morning. Others kept streaming in for hours. By midday the lines of pedestrains were long and thick as they proceeded through the city to the park. It was a perfect day for an outdoor gathering -- the winds brisk but the sun warm, and the people responded in keeping with that setting. They were patient and friendly and in good spirits.

For some of us, Grant Park remains a painful memory. The park became the symbol of the brutality and violence that marked the ending of the tumultuous Democratic convention in 1968, and the thousands who filled it then formed something of an American army in opposition to the American political leadership of that era. Tension and anger were the hallmarks of that rally in the park a decade ago, and the chemistry between police and people was combustible.

Today goodwill prevailed in the crowd of 1.5 million -- the largest to greet the pope so far on his American tour. The police were smiling and mingling without any air of heavy officiousness. "Have a good day," one Chicago cop kept saying to people as they entered the park.

Grant Park was filled with families. They sat on blankets or folding chairs and ate picnic lunches. Many carried palm fronds. Even the air of inevitable hucksterism was more subdued.

In New York the other day, after the pope completed his United Nations address, the barkers sprang up as if from nowhere in the streets. They were bellowing, "Pope buttons one buck, pope buttons one buck," and aggressively pressing a variety of papal souvenirs on passersby.

That wasn't the case in Chicago today. Outside the Palmer House, where our traveling papal party spent the night, a vendor had posted a sign offering "box lunches to go." But at $5 you got fried chicken, potato chips, a roll, an apple, a brownie, and beverage. Which is more in food, and considerably cheaper in price, than breakfast inside the hotel this morning. And on Michigan Avenue, young men were selling pictures of the pope -- but without the raucous tones of New York -- and here you got five pictures for a buck. Chicago, which is supposed to be so boisterous compared to New York's sophistication, on this day proved more subdued in manner and less commercial in character.

The pope's message before the crowd in the park was another mixture of temporal observations and religious concerns. Binding the two was the common thread of unity.

He wanted to speak as an evangelist about the unity of the Catholic Church, he said, but also about the unity of the American people. For all their diversity, all their multi-faceted complexities, Americans have had a common purpose, the pope said: "One nation formed of many people, e pluribus unum." Three times he gave that Latin refrain to sum up his understanding of the meaning of America, and ended that part of his message by saying:

"Again e pluribus unum: you became a new entity, a new people, the true nature of which cannot be adequately explained as a mere putting together of various communities."

So, too, he said, is the Catholic Church "composed of many members and enriched by the diversity of those making up the one community of faith." Then the pope appealed for "harmony and consistency of doctrine," and urged Catholics to reconcile their internal theological differences.

"Let love then build the bridges across our differences and at times our contrasting positions," he said. "Let love for each other and love for truth be the answer to polarization, when factions are formed because of differing views in matters that relate to faith or to the priorities for action. No one in the ecclesiastical community should ever feel alienated or unloved, even when tensions arise in the course of common efforts to bring the fruits of the gospel to society around us."

His words may not achieve his wish of unity, and undoubtedly the religious controversies will continue. But as only one of many who watched today, again it was John Paul, the person, who made the deepest impression. It was the way he addressed the crowds or sat with his eyes deeply shut in prayer, a look approaching plain on his face, that will be remembered.