Light (both natural and otherwise) is an essential tool in photography - here's a gallery dedicated to light use in photos, including low-light photography, black and white available light photos, night and morning photos.
Sunset on Sedona (AZ) Red Rocks with Moon
© Light _Looking For The Muskrat
© Michelle CampbellSundown at Golden Gate
© Kerry DragerA Space Needle Sunset
© Patricia MarroquinMS-1478
© Jim ZuckermanColosseo alla Notte
© Dave B. Ventimiglia