They sent him their wish lists, sat on his lap, and left cookies and milk for his arrival. Now the only thing left for children to do is track Santa's progress as he delivers gifts around the world on Christmas Eve.

Thanks to the folks behind the North American Aerospace Defense Command (NORAD) website, families worldwide can now follow Santa's Christmas journey in real time.

The tradition started in 1955 after an advertisement for Sears Roebuck & Co. misprinted a telephone number for a special "Santa hotline." Instead of reaching Kris Kringle, the number put kids through to the Continental Air Defense Command (CONAD) Commander-in-Chief’s operations, according to a description on the NORAD Tracks Santa Facebook page, which has more than one million "likes."

In addition to keeping tabs on Santa's whereabouts, there is plenty to do on NORAD's Santa-tracking site. Check out Kids' Countdown Village, which has more than two dozen games for children to play.

Not near a computer today? NORAD's Santa Tracker is mobile, too. Download the Android or iPhone app and let your kids track Santa from your phone.

Looking for additional ways to track Santa? Follow NORAD on Facebook, Twitter and Google+.

Merry Christmas and have fun!