This is what goes into putting together a major Fourth of July fireworks show

Fireworks and the Fourth of July go hand in hand, but for the biggest shows in the United States, as soon as one celebration is over, it's time to start getting ready for next year.

AmericaFest in Pasadena, California, is the biggest fireworks show on the West Coast. Over a span of 30 minutes, Pasadena sets off 2.5 tons of fireworks shells ranging in size from 3 inches to 12 inches. It takes 20 pyrotechnicians to set up the program, and two people to control everything from inside the Rose Bowl stadium. Fireworks that will be used in the finale are covered with foil ahead of time to keep moisture out, as they are connected by something called quick match, which burns at 100 feet per second.

To keep things fresh, new designs are dreamed up every year, and for 2017, AmericaFest will debut a firework called the Magic Peony — a happy face that strobes and blinks inside a firework that "will just appear out of nowhere," one technician told CBS Los Angeles. For up close photos of the fireworks displays before they are lit, visit NBC Los Angeles, and watch the video below. Catherine Garcia

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