BALTIMORE (WJZ) — Just before the clock strikes midnight, fireworks blast and “Auld Lang Syne” is sung, there are hours of work that go into preparation.

Gigi Barnett takes a look behind the scenes at this year’s fireworks display.

High in the sky over Baltimore’s Inner Harbor, fireworks will mark the start of 2013. But before that, there is plenty of preparation.

Engineers from Pyrotecnico have worked around the clock, even in snow, to assemble two barges packed with nearly 2,000 shells of fireworks.

Technician Ryan O’Neil says matching music to the light in the sky is tricky.

“With our special people at Pyrotecnico, that’s what they do. They set up, they script it so that way when a certain note hits, certain fireworks hit. So it takes a lot of time and effort to do,” said O’Neil.

This is the fourth year the city has invited Pyrotecnico back to Baltimore to create and coordinate the fireworks display. But it’s the first time the Orioles have sponsored the event. For that, there are some surprises in this year’s show.

“This year’s music will include Orioles fan favorite songs ‘Orioles Magic’ and ‘Glad You Came’” said Diane McConkey, Office of Promotion & the Arts. “A great time to end an amazing 2012 season for the Baltimore Orioles and kick off 2013 in the right way.”

Once technicians are finished assembling the fireworks, the barges have been strategically placed so that folks can see the fireworks wherever they are around the Inner Harbor.

“We’re glad to see that they like our show every year, they like our set up and we have a good time coming back every year” O’Neil said.

More than 50,000 people are expected to see the fireworks, which begin one second after midnight.