A Lenticular Cloud Over Wyoming

Is that a cloud or a flying saucer? Both, although it is surely not an alien
spacecraft. Lenticular clouds can be shaped like a saucer, and can fly in the sense
that, like most clouds, they are composed of small water droplets that float on air.
Lenticular clouds are typically formed by high winds over rugged terrain and are
particularly apparent when few other clouds are in the sky. Lenticular clouds can
take on particularly strange, layered shapes. Above, a couple stopped their car near
Yellowstone National Park in Wyoming, USA to photograph this lenticular cloud behind
picturesque windmills.