PITTSBURGH (AP/KDKA) — It’s Christmas Eve, which means NORAD is busy keeping track of Santa’s journey around the world.

The wildly popular NORAD Tracks Santa operation is launching its 61st run at Peterson Air Force Base, Colorado. Volunteers will answer phone calls and emails and post updates about Santa’s storybook world tour on Facebook and Twitter.

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You can follow Santa on NORADSanta.org, or on the official Facebook and Twitter accounts.

Here’s a look at the Christmas tradition:

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HOW DOES IT WORK?

Starting at 4 a.m. MST Christmas Eve, children can call a toll-free number, 877-446-6723 (877-Hi-NORAD) or email noradtracksantaoutlook.com to ask where Santa is on his fabled journey.

Volunteers sit elbow-to-elbow in conference rooms at Peterson Air Force Base, NORAD’s home, answering phones and checking computer-generated maps projected onto big screens. First lady Michelle Obama traditionally answers calls via a remote hookup, but Noel said it was not yet known if she will participate again this year.

Elsewhere at the Air Force base, volunteers update NORAD’s website (www.noradsanta.org), Facebook page (facebook.com/noradsanta) and Twitter feed (NoradSanta).

Last year, the website had 22 million unique visitors, Noel said.

Volunteers work in shifts, taking the last calls at 3 a.m. MST Christmas Day.

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WHY DOES NORAD ‘TRACK’ SANTA?

It started in 1955 when a Colorado Springs newspaper ad invited children to call Santa Claus but accidentally listed the number for the hotline at the Continental Air Defense Command, NORAD’s predecessor.

Air Force Col. Harry Shoup took a call from a child and thought he was being pranked. When he figured out he was talking to a little boy, he pretended he was Santa.

More children called, and Shoup instructed airmen to play along.

It’s now a tradition, beloved by kids and the military. Volunteers range from generals and admirals to enlisted men and women, who sometimes report for telephone duty in military uniform and a Santa hat.

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WHAT IS NORAD?

The North American Aerospace Defense Command is a joint U.S.-Canada operation that defends the sky over both nations and monitors sea approaches. It’s best known for its Cold War-era control room deep inside Cheyenne Mountain – now used only as a backup – and for NORAD Tracks Santa.

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