More than 5,000 people climbed the winding roads through Arlington National Cemetery to the Tomb of the Unknowns yesterday morning to honor those who, in the words of cemetery Chaplain John Morrison, "sacrificed all of their tomorrows so that we might have our todays."

Under gray and threatening skies, the Memorial Day pilgrims heard Vice President Quayle caution that the United States must remain strong militarily because "the world is still a dangerous place."

A similar theme was repeated hours later when an estimated 2,000 people stood in the rain at the Vietnam Veterans Memorial to hear Maj. Gen. Patrick Henry Brady, Army chief of public affairs. He warned "the greatest threat to peace is the perception that there is no threat."

But the largest crowd for Memorial Day observances was in Annapolis, where the rain held off, allowing the Blue Angels, the Navy's precision flight team, to complete their always dazzling annual performance.

As thousands watched on land and water, six F-18 Hornet fighter jets danced in ominous clouds above the Severn River for a half-hour, sending guttural screams across a city filled with graduation-week visitors to the U.S. Naval Academy.

"They were outrageous," said Tom Prendki of Glen Burnie, who spent the night aboard a friend's boat in Annapolis Harbor to get a good view of the aerial acrobatics.

The Blue Angels' show was one of the few Memorial Day activities that wasn't dampened by the cool, dreary weather, which periodically soaked resort beachgoers and neighborhood picnickers alike. And the weather did little to ease the usual traffic backups on the Eastern Shore.

At 5 p.m. yesterday, cars were stacked for 15 miles from Wye Mills to Kent Narrows just east of the Bay Bridge. And that, of course, was only the beginning. "Any weekend in summer is going to be like this," said Sgt. Kenneth Thrasher of the Maryland State Police. "Face it."

Across the metropolitan area, smaller crowds gathered for local parades, shopping-mall sales and back-yard barbecues made precarious -- or moved indoors -- by the weather. The official observances at Arlington and the Vietnam Memorial completed a weekend of events honoring the nation's war dead.

"We have been surprised in the past -- by Communism, Nazism, radical Islamic fundamentalism," Quayle told those gathered at Arlington. "Though we may be surprised again, let us always be prepared."

Honoring those who made the "ultimate sacrifice to preserve our freedom," he singled out Army Spec. Alejandro I. Manriquelozano, one of 23 Americans killed last year in the invasion of Panama. And he urged Americans "to renew our solemn pledge to remember" American military personnel missing in action.

Quayle received two standing ovations from a crowd well-primed by the U.S. Army Band and Chorus. But he was not the center of attention for spectator Mary Ann Williams, a professor at Ohio State University.

Williams and her husband made the seven-hour drive to Washington on Saturday with their friend Vivian Mason, who buried her 82-year-old husband, Sam Mason, a former Army captain, at Arlington in February 1989. "I came to be educated," Williams said, "and to take something back" to her communications students in the Department of Black Studies.

"They've got to know that we have a place here. My heart just pounded when I saw Colin Powell march in." Powell, a four-star general, is the first black chairman of the Joint Chiefs of Staff.

Williams leaned close to Mason during the ceremony, now and then sliding a protective arm around her shoulders. Mason carried with her the map to her husband's grave -- one among 214,000 graves, No. 3453, Section 28 -- which she had decorated that morning with a cross of red, white and blue flowers.

Mason first attended the Memorial Day ceremonies at the cemetery last year, three months after her husband's death. "I'm coming back every year till I'm buried here," she said.

Tom O'Donnell, of Landenberg, Pa., waited eight years to visit The Wall, the Vietnam Memorial. It was "hard -- very, very hard," said O'Donnell, who served in Vietnam with the Army's 1st Air Cavalry Division, D Company. After the ceremony, he picnicked with his family at a pond beside the monument to the signers of the Declaration of Independence, undeterred by the dreary weather.

In a way, he said, it was appropriate to the occasion.

A different kind of memorial was dedicated in Timonium yesterday by the families of 11 Maryland men killed by terrorist acts.

The 12-foot bronze-and-granite statue, called the Children of Liberty Memorial, depicts a woman's hands holding a folded American flag to her chest. It is inscribed with the names of nine men who died in the 1983 attack on the U.S. Marine barracks in Beirut; Robert Stethem, of Waldorf, who was killed during the hijacking of TWA Flight 847 in Beirut in 1985; and one man who was killed in the 1988 bombing of Pan Am Flight 103 over Lockerbie, Scotland.

Staff writers Sue Anne Pressley and Ruben Castaneda contributed to this report.