This is a long exposure photograph of the Golden Gate Bridge in San Francisco, California taken a night. The lights of the cars passing over the bridge trace light trails along the deck of the bridge. In the background behind bridge are the city lights in San Francisco. There is a mist in the air coming off the Pacific Ocean. The lights at the top of the bridge's towers are lighting up that mist, creating a soft glow in the sky just above the bridge.
More info on the original photo can also be found on the artist's website, DavidKunzman.net.