HOLT, Fla., Dec. 24, 2019—Santa Claus has begun his yearly holiday journey visiting children around the world.

His first stops were in eastern Russia and Asia.

U.S. North American Aerospace Defense Command, also known as NORAD, is tracking Santa’s trip on its Santa Tracker website that includes all types of online games for young and old alike.

The defense of Canada and the United States is NORAD’s top priority, tracking everything that flies in and around North America 24 hours a day, seven days a week.

However, every year on Christmas Eve, NORAD assumes the supplementary mission of tracking Santa as he travels around the world.

NORAD became the official Santa tracker in December 1951 when a Sears ad in a Colorado Springs newspaper misprinted a promotional phone number that belonged to Continental Air Defense Command, the precursor to NORAD.

From that point on, CONAD, then later NORAD became the official tracker of Santa’s journey.

Today, what began with one telephone call is now a huge Christmas undertaking.

NORAD relies on more than 1,500 volunteers to handle the phone with each volunteer answering about 40 calls per hour from around the world.