Volunteers are pulling on their Santa hats, phone lines are set, and tracking screens are ready -- NORAD Tracks Santa is primed for its 57th annual goodwill mission.
Santa trackers start taking calls early Monday, telling children -- and some adults -- when Santa is due at their house. The last shift won't end until nearly 24 hours later.
The number is 877-HI-NORAD or 877-446-6723.
Click the links below to track the updates on the web, Facebook and Twitter.
The operation is based at Peterson Air Force Base in Colorado Springs, Colo., home of the North American Aerospace Defense Command.
NORAD Tracks Santa began in 1955 when a newspaper ad listed the wrong phone number for kids to call Santa. They wound up calling the Continental Air Defense Command, NORAD's predecessor.