On December 24, 1955, the red telephone at the Continental Air Defense Command (CONAD) Operations Center in Colorado Springs, Colorado began ringing.
The red phone meant it was either the Pentagon or CONAD commander in chief General Earle Partridge on the other end, and their reason for calling would probably not be pleasant.
U.S. Air Force Col. Harry Shoup, director of operations at the center, rushed over to the phone and grabbed it.
“Yes, Sir, this is Colonel Shoup,” he barked.
Nothing but silence in response.
“Sir? This is Colonel Shoup,” he said.
Silence again.
“Sir? Can you read me alright?”
Finally, a soft voice on the other end.
“Are you really Santa Claus?” a little girl asked.
http://mentalfloss.com/article/32021/why-did-norad-start-tracking-santa