Pyrotechnic pros are hard at work packing shells into firing mortars. It's part of the nearly two weeks of wiring and positioning the fireworks for America's largest Fourth of July display.
Gary Souza designs all of the booms that lead to those oohs and ahs.
"Coordinating all five barges together, ten different computers, fifty people working on the show from all over the country that come in that are experts at doing this," Souza said.
It's the 39th year for the Macy's Fourth of July Spectacular. It will feature more than 50,000 shells and effects during a 25-minute show that begins at 9:20 p.m. Saturday.
Executive Producer Amy Kule says this year's theme is "brave."
"It is the last line of our national anthem, and we've taken that to heart," Kule said. "We're celebrating America, the spirit of America, and all of our brave heroes who have fought in every war."
The celebration on the East River will be visible from Manhattan, Brooklyn and, for the first time in years, Queens.
Last year, the fireworks were launched from three barges in the lower East River. This year, four barges will be anchored from East 23rd to 37th streets, and a fifth "double barge" will shoot rockets above the Brooklyn Bridge.
Souza promises that the show will blow your mind. His company spends months scouring the globe for the latest pyro power.
"We have some neon colors this year, in yellow, pink, orange and green. We're going to make these patterns of those highlighter kind of bright, vivid colors," he said.
And delight millions watching on the ground, and on live television across America.
"You turn everything else off that's going on in your life and in the world and just enjoy that moment, because it captivates you, and it brings you in and touches you on the inside as well as the outside," Souza said.
For everything you need to know about the Macy's Fireworks including where to watch and how to get there, just head to macys.com/fireworks.