The Pleiades rising behind the rustic cabins and outbuildings of the historic Larson Ranch in Grasslands National Park, Saskatchewan. Aurora shines to the left in the north while green airglow illuminates the sky to the east above the buildings. Grasslands is a Dark Sky Preserve. And the sky is very dark. All illumination here is natural  note the dark clouds seen against the brighter airglow-lit sky. (Photo by: Alan Dyer /VW PICS/UIG)