It was a Sunday afternoon about 4 or 5 o'clock in August 2007. My son, (who was 13 years old at the tim) and I had just left the bank on the corner of Sardis Rd North and Monroe Road. We we heading north on Monroe rd when I exclaimed, G_____, look at that! What is that?" G. did not know either, but acknowledged that he saw it too. I stopped the car in the right lane, and put my flashers on and we watched a very large gray disk. It was as big as 4 two story houses, if the houses were about 2500 square feet). The gray color was similar to "Battleship gray". The disk was vertical, as if it were a giant coin standing on it's edge. As we sat in the car, watching this, disk changed color! We watched it go from gray to white, similar to the color of a cloud. The way it changed was from the left side middle point of the diameter. The white color flowed from this point covering the top and bottom, until there was only a "pie piece" like wedge of gray left, and then that filled in. And it was gone, we could not see it. We did not see it fly away, we did not hear anything, it was just a part of the white cloud.