The final touches were made Tuesday for McAllen’s big Independence Day fireworks show.

The city’s annual Concert in the Sky fireworks show is the brightest in the Rio Grande Valley, according to the city of McAllen.

Crews spent three days setting up for it. 

Every explosive set gets its own wire, and lots of concentration. 

Glen Ufland said the fireworks will fire off in correlation with the music that's being played.

Fireworks were set up to go off in the right order.

The biggest firework is the 8-inch mortar, set aside from the rest of the fireworks for safety reasons. 

Ufland said it'll shoot up 800 feet, and its blast will be 400 feet wide.

“We don't want anything to fall on them, or if inadvertently anything should happen — like something should come out too low, or fire off too low and explode — we want to make sure nobody gets hurt,” Ufland said.

Firefighters are also staged near the fireworks site in case of an emergency.

The fireworks show is scheduled to begin at 9 p.m. Tuesday at Municipal Park, located at 1921 N. Bicentennial Blvd.