UFO Sighting in Cañon City, Colorado on July 14th 2014 – large cylinder slowly gliding over trees then suddenly disappearing

My husband and I were in our backyard, I happened to look in a NE direction and observed a huge cylinder object with a square on the back of the same material. I called my husband over and asked him what he thought it was, but neither of us knew. It suddenly disappeared. I don't know how no one else saw it, it was so big. It didn't make any sound. I often tell my husband that I just wonder what it was we saw that day, but he says that he doesn't quite remember it.