We're not sure how or why they appear, but you know it's the Christmas season in the Valley when saguaros atop Phoenix's two tallest points — Camelback Mountain and Piestewa Peak — get the Griswold treatment. We're not sure who lugs bulbs, garland, and battery-powered lights more than 1,000 vertical feet up the rugged trails, but it fills our hearts with holiday joy every time. The decorations appear and disappear mysteriously, as though they're the work of Christmas elves dispatched to the desert to bring a little Yuletide cheer, and they do more to get us in the spirit of an Arizona Christmas than even repeated viewings of It's a Wonderful Life, delicious tamales, or St. Nick in a Speedo.