Why Macy's 4th of July Fireworks show organizers say Hudson River is ideal

NEW YORK -- Meticulous prep work is underway to pull off what will be the nation's largest Independence Day celebration .

We're talking about the 48th annual Macy's 4th of July Fireworks show, which will return to the Hudson River a week from Thursday, starting at 9:25 p.m.

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Hudson River allows for bigger fireworks, organizers say

For the first time in a decade, organizers are switching rivers, going from the East River to the West Side on the Hudson.

"The Hudson River is a always been sort of a pyro's dream," said Gary Souza, Macy's Fireworks designer.

Souza said that's because it allows them to shoot off larger fireworks, some up to 10 inches and as heavy as 30 pounds.

"A 10-inch shell may burst over 1,000 feet wide," Souza said. "So we have to have a perimeter around there as a safety zone, in order to have those big shells."

Planning and executing the show is quite an undertaking

To put on the high-flying celebration, you have to start at the bottom, on barges.

"We have five barges, over 60,000 shells and effects," said Will Coss, executive producer of Macy's 4th of July Fireworks.

Coss' team is made up of more than 50 pyrotechnicians. When they're not carefully loading boats full of fireworks, some work on bomb squads outside of New York. Coss said safety is always a top priority when organizing and lighting off fireworks.

"These barges will be attached to tugs, so the tugs will take them out to. So that's where our people will be safely and securely covered during the show," Coss said.

Every shell has its own unique spot on each barge and connected to computers by a total of 75 miles of wires. That's enough to wrap around Manhattan twice.

It takes about a week to load the barges full of fireworks, but event organizers say it takes a year to design the show. They added there will be some unique fireworks that have been designed just for this year.