The barbecues, parades and gluttony contests were plentiful on Sunday, but many Americans celebrated the Fourth of July this year with an eye to fast-changing U.S. commitments at home and abroad.

Relatives of some of the victims of the Sept. 11 (search) attacks gathered in downtown New York to watch a 20-ton slab of granite placed as the cornerstone of the skyscraper that will replace the destroyed World Trade Center towers.

"It's a new beginning," said John Foy, whose mother-in-law was killed. "We all need to move on and rise above this."

Engraved to honor "the enduring spirit of freedom," the stone's placement marked the start of construction on the 1,776-foot Freedom Tower (search).

Meanwhile, in the turbulent Middle East, American personnel attended barbecues and played games amid new terror warnings from the State Department.

"We are always cautious wherever troops are, and today was like any other day," said Capt. Angie Blair, 27, at the As Sayliyah U.S. military base in Qatar (search). Personnel at the base celebrated the holiday with three-mile and six-mile races, followed by camel rides, games, a watermelon-eating contest and poolside barbecue featuring chicken, ribs and catfish.

And 15 months after the start of the Iraq war, fireworks, not missiles, lit up the night sky over Saddam Hussein's hometown of Tikrit. American troops and Iraqi National Guard soldiers jointly celebrated the holiday as well as Iraq's newfound sovereignty, feasting on hamburgers, hot dogs and traditional Iraqi dishes in one of the former dictator's old palaces.

Back home, Afghan leader Hamid Karzai (search) was awarded the Philadelphia Liberty Medal, given each July 4 by the nonprofit, nonpolitical Philadelphia Foundation to recognize leadership in the pursuit of freedom. The medal's $100,000 prize will go to support Afghan orphans, he said.

Torrential rain washed out the Independence Day parade in the nation's capital Sunday, but fireworks on National Mall proceeded as planned under cloudy skies. President Bush planned to watch the display from a White House balcony.

In Boston, a mother of two who normally spends Sunday nights singing karaoke with friends found herself on the bill for a bigger show — Boston's annual Fourth of July (search) Pops concert and fireworks display.

"It's just a dream," Tracy Silva said a few hours before her nighttime performance in front of a crowd of thousands, which she earned by beating out 700 competitors in the Pops' first talent competition.

Sunday was also a day for parades, picnics, fireworks and summer stunts such as the annual hot dog-eating contest at New York City's Coney Island (search).

For the fourth straight year, a rail-thin competitor outperformed much beefier opponents to take the title in the Nathan's Famous hot dog-eating contest.

Takeru Kobayashi of Nagano, Japan — just 5-foot-7 and 132 pounds — wolfed down 53½ wieners in 12 minutes, shattering his own world record. His nearest challenger gulped down only 38.

"I could have done a lot, a lot more," Kobayashi said through an interpreter.

In Manhattan, organizers billed the fireworks show as the largest pyrotechnic display in the country, with more than 36,000 shells exploding in concert with a tribute to the Statue of Liberty. The fireworks lit up the lower Manhattan skyline and thundered throughout the city.

Sometimes the holiday festivities produced the unexpected.

In Utah, two young bull moose, each more than 6-feet tall and weighing hundreds of pounds, crashed the Fourth of July parade in the mountains east of Salt Lake City, coming within a few feet of spectators.

"I told my family, that's something you don't see at the downtown parades," Jeff Worthington said after Saturday's celebration at Brighton.

Back in Boston, Silva sang her favorite song, "Your Daddy's Son," from the musical "Ragtime," backed up by the Pops orchestra and conductor Keith Lockhart. Her performance received a standing ovation, and Lockhart gave her an onstage hug.

"The Fourth of July has special meaning in Boston," Mayor Tom Menino said before a fife and drum corps dressed in Revolutionary War uniforms marched past. "Our country and everything we stand for started right here in these streets."

The Associated Press contributed to this report.