Archbishop Donald Wuerl, left, and Monsignor Walter Rossi, director of the Basilica of the National Shrine of the Immaculate Conception, show Pope Benedict XVI the ceiling of the Basilica in Washington, D.C., on Wednesday.

WASHINGTON — Thousands of worshippers began arriving at the Washington Nationals stadium today, eagerly awaiting an open-air Mass that will be presided over by Pope Benedict XVI.

A crowd of 46,000 is expected, and the demand for tickets doubled the supply, organizers said.

Barbara and Michael Loh of Williamsburg, Va., sat alone in the stands taking in the scene. They were among the first to arrive.

"I've been Catholic all my life and ... my dream has always been to see the pope," said Barbara Loh, tearing up.

At 5:45 a.m., more than four hours before the Mass, it was standing-room only on Metro trains.

Vendors hawked Vatican flags and souvenir buttons, but there were few takers as people hurried toward the stadium.

For others, there was nothing more important than getting in, and many people without tickets stood outside the Metro station with signs pleading for extras.

Patty Trail, 54, pastoral associate at a church in Virginia Beach, Va., drove overnight to bring two priests to the Mass. She didn't have a ticket but said she was happy to at least be in the vicinity of the pope.

"Just to be out here, just to be in the presence," she said. "D.C. feels different."

Benedict spent the first full day of his U.S. journey Wednesday sharing a platform with President Bush and laying out his analysis of the American church to the nation's bishops.

Before Benedict's arrival, polls showed most Americans knew little or nothing about him.Those who have watched him so far have found a German-born pontiff who speaks excellent English, appears vigorous for his 81 years, mostly prefers script to spontaneity and displays a keen sense of the critical issues facing his 65 million member American flock.One of the larger questions hanging over Benedict's first U.S. trip as pontiff was whether and how he would address the clergy sex abuse scandal, which has claimed thousands of victims, cost the church more than $2 billion in court costs and settlements and led six dioceses to declare bankruptcy.The answer: He's talked about it early, often and with conviction, although not to the satisfaction of many victims and their advocates.In an address to U.S. bishops Wednesday night at the Basilica of the National Shrine of the Immaculate Conception, Benedict called the scandal a "deep shame."He decried the "enormous pain" that communities have suffered from such "gravely immoral behavior."Advocates for victims have complained that no bishops have been disciplined for failing to warn parents and police about abusers.

Little Sisters of the Poor Sister Rose Marie, Sister Imelda and Sister Florine are among the first to arrive early this morning before the Papal Mass with Pope Benedict XVI at the Washington Nationals stadium in Washington, D.C. A crowd of 46,000 is expected.