For one day each year, the North American Aerospace Defense Command, better known as NORAD, adds a special mission: tracking Santa Claus.
Volunteers answer more than 130-thousand calls from children across the globe. The number is 1 (877) HI-NORAD ... that 's 1-877-446-6723.
You can watch Santa's progress around the world at NORADSanta.org.
Photo: KAREN BLEIER / AFP / Getty Images