HUNDREDS OF FOURTH of July gatherings across the country dub themselves "star-spangled celebrations," but to experience the real McCoy, you need to attend a Defender's Day celebration at Baltimore's Fort McHenry, the birthplace of the national anthem.

It was the successful defense of the fort 190 years ago, during the War of 1812, after a battering 24-hour bombardment from a British armada that inspired Washington lawyer Francis Scott Key to pen "The Star-Spangled Banner."

"If Key had lived in the modern day, he would have written one word, 'Yes!' But since he lived in a more eloquent age, he wrote a four-stanza poem," said Ranger Vince Vaise, lead organizer of Defender's Day.

Beginning Friday, Fort McHenry National Monument and Historic Shrine will host its annual three-day celebration to honor the victory that helped turn the tide of the war against Britain. According to Vaise, the weekend also commemorates the emergence of the flag as the quintessential icon for Americans to rally around during times of crisis.

Throughout the weekend, living history volunteers and rangers in period costumes will conduct flag-changing ceremonies, cannon and musket-firing demonstrations, and fife and drum concerts. Historians and rangers will give talks on a variety of topics, including combat surgery and the role of religion in the battle.

On both Saturday (from 10 to 4) and Sunday (from 10 to 2), a special children's area inside the fort will feature hands-on activities for youngsters. They can try on kid-size replicas of period fashions, learn how to wield a wooden sword and try their hand at picking up cannonballs. Children's author Amy Winstead will sign copies of her book, "The Star-Spangled Banner," which describes Key's writing the anthem through the eyes of a small boy who was oystering near the fort.

The high point of the festivities, according to Vaise, is the Saturday evening program. Local dignitaries will speak, and the U.S. Army Field Band will give a special musical tribute to the heroes of Sept. 11, 2001, including those who died in the terrorist attacks, those who rescued survivors, the survivors themselves and their families. Then a mock ship-to-shore bombardment will begin on the fort with a special pyrotechnic combination of real projectiles and fireworks. Tchaikovsky's "1812" Overture will accompany the "bombs bursting in air." (Note: Although it has become a standard at American patriotic celebrations, this music was written to commemorate the Russian defeat of Napoleon in Moscow.) "The fort is in its glory," Vaise said. "You see the silhouette of the fort, the soldiers on the ramparts, and for two or three minutes, you almost feel like you're there."

Vaise suggested that visitors bring blankets and lawn chairs for the evening program because the park does not provide any seating. Visitors are also welcome to bring picnics and coolers, however all items will be subject to search.

During a recent visit to the 18th-century fort, which is on a 43-acre peninsula about three miles from the Inner Harbor, my family and I sensed a reverence from both the staff and visitors for the huge, 32-by-40-foot flag that billows (weather permitting) over the grounds. Living history volunteer Rick Manacle, dressed in period sailor garb that made him look like an extra from the "Pirates of the Caribbean" movie, passionately described his devotion to the fort.

"This is the only historic shrine in the national park system. When I think about how many people have fought and died under this flag This is where it all started!"

During our visit, we started with a 20-minute film in the visitors center that explained the events leading up to the Battle of Baltimore. The film ends with a rousing rendition of "The Star-Spangled Banner" just as a curtain pulls back to reveal the 15-striped, 15-star banner "so gallantly streaming" over the fort.

We spent another two hours wandering around the maze-like fort. Five buildings, including the enlisted men's barracks, commanding officers quarters and powder magazine, still stand in the interior of the fort. My daughters and I stood in narrow cells in the guardhouse, where Southern sympathizers, including the mayor of Baltimore and a newspaper editor who happened to be Francis Scott Key's nephew, were held as political prisoners during the Civil War. The fort was pressed into active military service well into the 20th century when it served as a hospital for wounded soldiers during World War I.

My husband, Alan, said the outer fortifications reminded him of the artwork of M.C. Escher, with staircases and high plateaus that seemed to melt into low gullies. The fort is surrounded by brick walls that enclose huge mounds of dirt topped with grass. These ridges are the famous ramparts that appear in the anthem. At the base of the ramparts is a dry moat. Along the portion of the fort that faces the river is another brick wall that makes up the outer battery. Here, thick black cannons point at various angles toward the water.

My daughters, ages 9, 7 and 5, thoroughly enjoyed scrambling over the ramparts and looking at all the sailboats in the Patapsco River.

Cyrus Deloye, a 9-year-old visiting from Chicago, was also delighted to wander through the battlements with his 5-year-old brother. When asked what he thought of the fort, he realized, with some prompting by his father, that the next time he was at a Cubs game and heard the national anthem he might think of Fort McHenry.

That proved true for my family, too. The Athens Olympic Games, which for our budding swimmers were inextricably bound to Baltimore swimming sensation Michael Phelps, now had another Baltimore connection. Every time we saw a laurel-wreathed Olympic champion watch the Stars and Stripes rise over the podium, we knew that we had stood where the anthem began.

DEFENDER'S DAY -- Friday, Saturday and Sunday at Fort McHenry National Monument and Historic Shrine, at the end of East Fort Avenue, Baltimore. 410-962-4290. www.nps.gov/fomc. $5, free for children under 17. The evening program beginning at 6 is free for everyone.

The Fort McHenry Guard cheers for the Stars and Stripes at the historic fort, where a pivotal victory 190 years ago in the War of 1812 inspired Francis Scott Key to write "The Star-Spangled Banner."