With four quick whistles, they were ready.
As that sound pierced the cool morning air, Polytechnic High School's " Marching 100" band snapped to attention, ready for its brief moment in history.
Two drum majors saluted; the majorettes stood still.
And as the presidential motorcade pulled in front of the Tarrant County Courthouse, the precision marching band began playing "Dixie," one of its signature songs.
The presidential limo slowed down.
President John F. Kennedy stood and raised his hand in greeting. Some say he waved, others believe he saluted.
In the blink of an eye, the president was seated and the motorcade left downtown that morning, Nov. 22, 1963, headed toward the then-Carswell Air Force Base to catch a flight to Dallas on Air Force One.
"We were some of the last people to see President Kennedy alive," said Jerry Winfield, a 65-year-old man who lives in Pecan Plantation near Granbury. "It was a little, small part of history that we got to see the president of the United States.
"Everything changed later that day."
Around the time members of the Marching 100 returned to school and got back to class, they learned the president they just saw had been shot and killed while riding in a Dallas motorcade.
But they are determined to remember the good moment in history -- when Kennedy heard them and acknowledged their band.
Some members of that 1963 band will gather for a ceremony Sept. 25 at Polytechnic to dedicate the historic photo of Kennedy greeting the band.
James Eli "Jim" Smith, Polytechnic's 1963 band director, is expected to present the framed photo and two written pages of his recollection of the event to the school.
Winfield remembers the excitement that morning nearly 50 years ago.
He and the other band members were decked out in their basic black uniforms trimmed with orange.
They lined up, row after row, on the courthouse steps, surrounded by throngs of people hoping to catch a glimpse of the president.
And they waited.
They heard the roar of the crowd as the motorcade approached; they saw the flashing lights from dozens of police motorcycles and car escorts.
With the four whistles issued by Smith, the band director, the band stood at attention. The two drum majors saluted the president with their batons, and the band began playing Dixie.
"It was super exciting to see him," said Marcus Gann, 67, one of the drum majors, who now lives in Savannah, Ga. "They were probably 15 to 20 feet away from us."
The motorcade slowed down even more, possibly stopping briefly, as Kennedy stood in the car and either waved to or saluted the band.
"It was so exciting," said Jaqulyn Landress Curry, 66, a majorette who stood in front of the band that day. "This important person was coming down in front of us, so close you could almost touch him.
"I was thinking my dream was coming true," said Curry, who lives in Fort Worth. "Here's our president, and we were chosen to do this, and he's really in front of us, and I'll never be this close to a president again."
Ronda McDowell Needham, a herald trumpet carrier who stood behind the majorettes, still remembers the pride she had at being part of the band -- and performing for such an elite audience -- that day.
"It was such an honor," she said. "I was thinking, `That's the president of the United States and the first lady.'
"I could see them very well," she said. "She was beautiful; he was handsome and tan."
Winfield said he was surprised the president's vehicle slowed down in front of them.
"The president stood and acknowledged us," said Winfield, who played the saxophone. "I guess it was spur of the moment.
"We weren't expecting anything."
Once the motorcade was out of sight and the band had finished performing, members of the Marching 100 loaded up the school buses.
On the ride back to school, they talked about seeing the president and his smile -- and Jackie Kennedy and her beauty. They talked about the crowd and the rare opportunity to play for the country's leader.
When they got back to school, they could hardly believe what they heard.
The president had been shot and killed in Dallas.
"It was unbelievable that we saw him . and then hours later we heard he had been shot," Gann said.
"How could that have happened? We just saw him," Winfield said. "Everybody was wondering what would happen to the country. The band director tried to reassure everyone and said the country would recover from this."
Curry said she didn't believe the news at first.
"We thought it wasn't real and he had to be OK," she said. "I was scared to death. It couldn't be real. We just saw him."
Needham was sitting in the cafeteria when she heard the news.
"The world stopped for me," she said. "The world froze for me for 10 seconds or however long. Then we all looked at each other. It was very quiet, and everyone was talking very quietly.
"People say they'll never forget where they were or what they were doing" when they heard the news, she said. "That's true."
And all those who were part of the Marching 100 will forever be bound by the rare experience of performing for the president on such an historic day.
Smith's lasting memory:
"That day, the spirit of Camelot rode in an open car down Main Street in our hometown, stopped, stood to acknowledge our efforts, then left us far too soon."