This scene's histogram ran into both the left (dark) and right (bright) sides. Its tonal range was greater than the camera could handle. The cause of the problem was the impending sunrise at the upper right side - blowing out the sky in that region.

The technique used to solve this problem combined two images (taken off a tripod) - one underexposed one stop but with the highlight detail present (upper left image), and one overexposed one stop but with the shadow detail present (upper right image). These two images were combined in Picture Window Pro using the overexposed image as an overlay and using a density mask (a mask layer whose opacity matched the lightness/darkness of the underexposed image). The resulting image (bottom) contains the "best of both worlds" and extends the camera's dynamic range by two stops.