PHOENIX -- It's called the Mystery Tree, a juniper located in the median just north of the Sunset Point rest area along Interstate 17.
Every year around Thanksgiving, for the past 30 years or so, the tree has been fully decorated. The big question is who's responsible for the handiwork.
"I've never heard who actually does (the decorating) and I like the mystery to stay that way," said Doug Nintzel of the Arizona Department of Transportation.
He said department crews aren't decorating the tree with ornaments and tinsel. Officer Carrick Cook, a spokesman for the Department of Public Safety, said patrol officers aren't the elves.
"About six to eight years ago, the group that does decorate it actually sent us a Christmas card and they took a picture of themselves with their backs turned to conceal their identity," Cook said. "It's a tradition and an interesting story and people enjoy that the tree is a mystery and nobody has been able to solve it."
Cook said the tree is really a miracle tree, because it has survived several brush fires.