A Beautiful Cumulonimbus Cloud

During the flight from Washington to Denver late yesterday, we passed by this spectacular cumulonimbus cloud. The object at the bottom of the photo is the left wing of our aircraft. At the time this was taken, we were cruising at about 40,000 feet and somewhere over the state of Indiana. As you can see, the sun was low in the sky and illuminated the right-hand section of this cloud, giving a nice 3-dimensional perspective. The top of the cloud was quite a bit higher than we were flying. I enjoyed seeing this as we flew by, wondering if there was an active thunderstorm occurring below us on the ground.