NEW YORK -- St. Patrick's Day celebrations unfolded across America Saturday, led by the nation's oldest and largest parade which paused for a silent moment to honor the dead in a city healing from terrorism.

As bagpipers played the last chords of "God Bless America," thousands of marchers and hundreds of thousands of spectators along Fifth Avenue faced south in silence toward where the World Trade Center towers had stood.

"Many of those who were lost on Sept. 11 would otherwise be marching proudly. ... We know their spirit marches with us," said Ireland's president, Mary McAleese, who joined the New York parade for the first time.

The parade, like others across the country, was filled with small, poignant tributes to the victims, but it also carried the usual sprightly twists of Irish humor.

President Bush marched with politicians and firefighters in Chicago, a city so Irish it dyes the Chicago River green for the occasion.

"People are generally good and fun-loving and they need little reason to show it -- this day has a lot of tradition about being a happy day," said Steve Healey, 33, an engineer who ran in a pre-parade race Saturday in Rochester, N.Y., carrying an Irish flag.

Fewer shenanigans

Despite its reputation for treating the day as a post-Mardi Gras beer bash, Savannah, Ga., celebrated by playing up patriotism and toning down the shenanigans. The biggest cheers were reserved for marchers wearing camouflage and police blues.

"We heard St. Patrick's Day is over the top down here, and we've had an unbelievable reception from people," said New York police officer Jack Bishop, pausing for photos and kisses from women rushing out of the crowd.

Parade organizers in Wenatchee, Wash., counted on keeping tradition alive with a no-show today from their invited grand marshal -- former Enron Chairman Kenneth Lay.

It's a standing joke of the Loyal Order of Hibernians there to choose a national newsmaker who is unlikely to appear. Past no-shows include White House intern Monica Lewinsky and Filipino dictator Ferdinand Marcos.

In Boston, where 23 percent of residents report Irish ancestry -- the highest percentage in the nation according to the census -- the big parade was scheduled on St. Patrick's Day, today.