In October 2017 the sky turned pink. The phenomenon was due to the remnants of Hurricane Ophelia dragging in tropical air and dust from the Sahara; the debris from forest fires in Portugal and Spain also played a part.
The dust gets picked up into the air and goes high up into the atmosphere which causes shorter wavelength blue light to be scattered, making it appear pink. This weird pink light was quite disturbing.
You would almost expect to see the four horsemen galloping out of the sky.