The Chicago Skyline in HDR

HDR (High-Dynamic-Range) is a technique where you take the same picture with multiple exposures (underexposing, overexposing, and the correct exposure) and then mash them together with software in post processing. This technique allows the picture to process in much the same way we would view it with our eye. In a scene with a stark contrast of bright light and darkness you can get a "correct" exposure throughout the picture rather than some of the picture that looks "correct" and the rest of the picture underexposed (or overexposed).

Here are several HDR photos of the Chicago Skyline from different times of the evening. You'll see the sky maintains it's natural color while the buildings and city lights also maintain their brightness.