Unusual line of clouds drifting across the sky. Reminded me a little of the Dementors in the Harry Potter films.
Cornwall, Ontario, Canada.
Sony Alpha 700, Sigma 28 to 300 at 28 mm, circular polariser
iso 100, spot metered, -1.3 ev, f11, 1/125 second
The deep blue is achieved with the camera lens/polariser being at 90 degrees to the sun and by underexposing. Contrast slightly increased in PSE (+12).