In a Catholic-founded state and a city steeped in church tradition, Pope John Paul II concluded his five-day U.S. visit today with calls for religious perseverance, personal responsibility and protection of human life at all stages.

"I say to you again, America, in the light of your own tradition: Love life, cherish life, defend life, from conception to natural death," the pope said before boarding an airplane for Rome.

For Baltimore, a proud but struggling city that is the cradle of American Catholicism, it was a day to exult in pageantry, pomp and plain old-fashioned fun. Devout parishioners, many praying quietly, coexisted easily with non-Catholics and cheering parade-goers who munched "popecorn" and "popearoni pizza" from vendors.

Hundreds of thousands of people, buoyed by a sun-kissed sky and the historic thrill of the first papal visit to Baltimore, jammed Oriole Park at Camden Yards, downtown parade routes and other sites to hail the church's leader. Many sang, cheered and shamelessly wept in the presence of the frail but charismatic 75-year-old pontiff.

With funky pop tunes giving way to soaring organ processionals, the ceremonies were as eclectic as the 900 million-member worldwide church he oversees. Before John Paul II celebrated Mass in Camden Yards, performers in Old World costumes danced to African American gospel songs belted out by the Urban Mass Choir. In one of the day's odder moments, the Polish-born pope slowly waved to the stadium crowd from his Popemobile as Boyz II Men sang their hit song, "Thank You."

The pope's 10-hour Baltimore visit came after four days in the New York area, where he stressed the United States' moral responsibility to help the less fortunate, especially immigrants and poor people. He continued that theme today, saying democracy and freedom carry with them certain obligations. Twice during the day, he spoke of protecting life at all stages, an allusion to the church's stance against abortion and euthanasia.

In today's homily, or sermon, the pope also addressed such classic religious themes as patience and faith in God, and spreading the Gospel. He acknowledged that Catholics sometimes "are tempted to discouragement or disillusionment," and he urged them to "not lose patience with God."

Although John Paul often seemed a gentle and supportive grandfather, he admonished Catholics that faith in Christ is no casual matter. "The Gospel of Jesus Christ is not a private opinion, a remote spiritual ideal or a mere program for personal growth," he said. "The Gospel is the power which can transform the world."

Almost as if teaching a U.S. history lesson, the pope cited the Star Spangled Banner, the Bill of Rights and Abraham Lincoln's Gettysburg Address. He noted that Lincoln had asked "whether a nation conceived in liberty and dedicated to the proposition that all men are created equal' " could "long endure." The pope then said: "Every generation of Americans needs to know that freedom consists not in doing what we like, but in having the right to do what we ought."

John Paul, a former professor of moral theology who prefers the title Supreme Pastor of the Church, spoke of the "new evangelization" of Roman Catholicism as the third millennium approaches. He urged American Catholics to become foreign missionaries and to capture the spirit shown by Catholic youth during his visit two years ago to Denver.

"Today I offer this Mass for strengthening of that vitality and Christian courage at every level of the Church in the United States," he said. "This is what the successor of Peter has come to Baltimore to urge upon each one of you: the courage to bear witness to the gospel of our redemption."

Portions of the Mass were spoken in several languages, but the day had a distinctly Baltimore flavor. Seated in front of a 34-foot cross near center field, John Paul acknowledged Maryland as "the birthplace of the {Roman Catholic} Church in colonial America."

English Catholics founded the Maryland colony in 1634 and created the nation's first diocese, in Baltimore, in 1789. In recent years, however, thousands of Catholics have left Baltimore for its suburbs, putting a strain on its inner-city churches. Cardinal William H. Keeler, the archbishop of Baltimore, told the Camden Yards crowd that racism, poverty, drugs and crime "take a daily toll" on people's lives.

In his homily, John Paul urged his audience to care for the less fortunate and have faith in God. Thousands responded with loud cheers, clasped hands or tears of joy.

Touching moments punctuated the day. Thousands cheered and waved pennants as the pope led a midday parade from Camden Yards through downtown Baltimore to the Basilica of the Assumption, the first Roman Catholic cathedral in the United States. From the Popemobile, the pontiff leaned to his right and blessed a 75-year-old Dundalk woman who had fainted during the parade and been placed on a stretcher.

For some, the ecstasy of seeing the man they consider the Vicar of Christ was almost too much to bear. Eileen Walsh, 47, of Baltimore, burst into tears when John Paul entered Camden Yards in the Popemobile.

"I have no words to describe how I feel," said Walsh, who later appeared to hang on every word the pope uttered. "I never thought I would see him in my lifetime. . . . This is an overwhelming feeling."

Earlier, when he arrived at Baltimore-Washington International Airport, John Paul gently embraced two children -- Melissa Brent, 7, of Columbia, and Justin Farinelli, 9, of Pasadena -- who presented him with black-eyed Susans, the state flower. He then playfully tapped Raymond Glendening on the cheek when the teenager's father, Maryland Gov. Parris N. Glendening, noted that Raymond attends a Catholic high school.

A pre-Mass pageantry of music and dance began in Camden Yards at 7:30 a.m., more than three hours before the pope's arrival. About 11 a.m., the Mercedes-Benz Popemobile entered the stadium to thunderous applause and the pounding beat of Boyz II Men. For many Catholics, the ballpark seemed to give way to a tangible embodiment of their faith -- as vivid as the swirling dancers in rainbow colors, as personal as the deceased family members they prayed for, as cozy and familiar as the old Bromo Seltzer clock tower peeping over the outfield wall.

"It seems like when I leave here, there will be no more sin, no more crime," said Philathia Hepler, 40, of the District. "Like we could walk out of here and each one of us do right -- each one teach one -- and we could change the world."

The pope, a soccer goalie as a teenager, seemed to take easily to Camden Yards' sports atmosphere, subdued though it was with the beer and soda advertisements covered for the day with black plastic.

Throughout the service, a portion of which John Paul read in Spanish, the pope walked slowly with a slight limp. He remained seated as he read the homily, a priest holding a white umbrella to shield him from the glaring sun.

Today's Mass was the fourth in as many days conducted by John Paul before huge outdoor audiences. He celebrated Mass on Thursday at Giants Stadium in New Jersey; Friday at Aqueduct Racetrack in Queens, N.Y.; and Saturday before 125,000 in Manhattan's Central Park. He also addressed the United Nations and spoke to seminarians in Yonkers, N.Y.

More than 50,000 Catholics, having won tickets in church lotteries, attended today's Mass. Later, hundreds of thousands more lined the parade route. Baltimore police and city publicists estimated the entire crowd at more than 300,000.

Among them was Breni Enriquez, a 25-year-old Bolivian immigrant who lives in Herndon and arrived Saturday night with four bus loads of parishioners from San Carlos parish in Arlington. Her group had slept on the sidewalk opposite Harborplace to assure their place along the parade route.

"All of this is worth it to see the pope," Enriquez said. "He's the closest living thing to God."

People at Baltimore's Inner Harbor watched the stadium proceedings on large video screens. Some prayed along during the Mass; others talked quietly or milled about.

A man in suspenders and flannel slacks stood with eyes closed and hands raised in the air as he recited the Lord's Prayer before the start of Communion. Standing next to him, with his head bowed, was a homeless man who stood atop his bagged belongings repeatedly saying, "Hallelujah."

Another man, roller blading down Calvert Street, came to an abrupt stop when he saw the pope on the big screen blessing the Communion hosts and wine, and he knelt on one knee to pray.

At the parade's end, the pope had a 2:30 p.m. lunch with about 20 people at Our Daily Bread, a church-run soup kitchen that typically feeds hundreds daily. He shook hands with the adults and kissed six children on the forehead and squeezed their cheeks.

Donna Campbell, 32, an unemployed single mother of three, was astonished to be seated next to the pope. "I told him about my children's interests and that they liked to play basketball," Campbell said later. "I don't know if he understood all that I was saying. He just nodded his head.

"I hope this experience will bring more African Americans back to the Catholic Church," Campbell said. "I hope to take my experience of meeting the pope into the community in order to teach someone else."

She added that John Paul ate "everything on his plate," including a chicken-and-rice casserole and chocolate chip cookies.

The only organized protest against the papal visit occurred nine blocks from Camden Yards. About 100 abortion rights advocates, gay rights supporters and others gathered briefly around the George Washington Monument in Mount Vernon Place to march and shout slogans.

After the Pope rested at Cardinal Keeler's residence, he met privately with officials and supporters of Catholic Relief Services at the Basilica of the Assumption of the Blessed Virgin Mary, the first Roman Catholic cathedral built in the United States. When the meeting ended, John Paul walked slowly before the altar and knelt silently on yellow cushions for nearly five minutes.

During an interfaith prayer service at the Cathedral of Mary Our Queen, the pontiff told an audience of 1,300, heavily sprinkled with Maryland political leaders, that they must work to continue the state's historical commitment to religious freedom. He also urged the worshipers to "defend the right to life of every human being from conception to natural death. . . .

"The challenge facing you, dear friends, is to increase people's awareness of the importance for society of religious freedom; to defend that freedom against those who would take religion out of the public domain and establish secularism as America's official faith."

Entering and leaving the 39-year-old cathedral, the pope touched the hands of many of the faithful and allowed them to kiss his ring. As he departed, he briefly held 22-month-old Graham Bernard Harrison, who recently was diagnosed with leukemia.

The child's mother, Patricia Harrison, said she was thrilled and hopeful: "It was very remarkable. The prayers, the faith and maybe the pontiff's blessing will help us."

Shortly before 8 p.m., a helicopter brought the pope back to BWI, where Vice President Gore and his wife, Tipper, rushed out to meet him. Gore spoke with the pontiff for 15 minutes about the war in Bosnia. Reporters, who were shuttled in and out of the meeting, heard Gore say: "I'm very hopeful that the cease-fire is part of a true peace."

In his farewell comments at the airport, the pope addressed the American people. "In our world as it is," he said, "many other nations and peoples look to you as the principal model and pattern for their own advancement in democracy. But democracy needs wisdom. Democracy needs virtue. . . . Democracy serves what is true and right when it safeguards the dignity of every human person, when it respects inviolable and inalienable human rights, when it makes the common good the end and criterion regulating all public and social life."

Also contributing to this report were staff writers Louis Aguilar, Amy Argetsinger, Dan Beyers, Anna Borgman, Bill Broadway, Deirdre M. Childress, Lisa Frazier, Hamil R. Harris, Peter Maass, Eugene L. Meyer, Phillip P. Pan, Fern Shen, Paul W. Valentine and Debbi Wilgoren; staff researcher Mary Louise White; and Metro administrator Lisa Heidemann. CAPTION: Pope John Paul II greets Cardinal William H. Keeler, archbishop of Baltimore, before celebrating a Mass attended by more than 50,000 Catholics in Oriole Park at Camden Yards. CAPTION: Thousands jam Camden Yards to watch Pope John Paul II celebrate Mass during the first papal visit to Baltimore. The pontiff sat in front of a 34-foot cross near the center of the ballpark. CAPTION: Pope John Paul II makes his way along Pratt Street in the Popemobile after the Mass. CAPTION: Above left, in pre-Mass pageantry, members of the Baltimore Young Adult Christian Clubs perform, holding boards that form the Maryland state flag. Above, Pope John Paul II tweaks the cheeks of Ivan Damian at a church-run soup kitchen, Our Daily Bread. Right, the pontiff presides over an interfaith prayer service at the Cathedral of Mary Our Queen. CAPTION: Far left, schoolchildren wave goodbye to the pope as he leaves the Cathedral of Mary Our Queen. Center, the pontiff leans over to kiss Erika Spivey, 6, as she and her parents greet him on stage at Camden Yards. Michelle Daniels, left, and John A. Jones clap and sing during the pre-Mass pageantry of music and dance in Camden Yards. CAPTION: Top, four priests line the bleachers at Camden Yards as they await the arrival of the pope for Mass. Above, a group of nuns on Pratt Street watches the rest of the parade after John Paul goes by in the Popemobile. At right, the pontiff kneels at the altar in the Cathedral of Mary Our Queen before addressing the faithful gathered there.