Every year, in a tradition that dates back to the Cold War, volunteers field tens of thousands of calls and emails from across the world, according to the North American Aerospace Defense Command. Children ask for Santa’s location, detail their Christmas lists and probe volunteers for other details.Those volunteers, who take two-hour shifts starting in the early morning on Dec. 24, wouldn’t be there if not for a typo in a local newspaper in 1955.

When Col. Harry Shoup picked up his secret hotline at Peterson Air Force in Colorado, he was expecting a call from a four-star general at the Pentagon, according to a  2014  StoryCorps interview with his children. “And then there was a small voice that just asked, ‘Is this Santa Claus?’ ” his daughter, Pam Farrell says.

His family says that Shroup was annoyed. The United States was nearly a decade into the Cold War, and the colonel was prepared for reports of a nuclear attack, not requests for Santa Claus. But when the child started to cry, he responded jovially. Then he asked for the boy’s mother.

The mother explained that a Sears ad in the newspaper instructed kids to call Santa “any time day or night.” But the newspaper had accidentally printed the number for Shoup’s private red phone, instead of the store’s. So as the calls came in, Shoup put his airmen on the phones to pretend to be Santa Claus. The tradition has continued for more than six decades, outliving its creator — Shoup died in 2009.

The “tracking” technology has evolved over time, said Maj. Todd Walter, a Mission Crew Commander with the Canadian Air Defense. “We use radar systems scattered across the world, along with satellites providing infrared imagery, we have Santa Cams scattered throughout the world, then jet fighters that also go out and intercept Santa.”