High Dynamic Range photos are produced by taking up to 9 multiple exposures of a scene, each at a different exposure value from under exposed to over exposed. The multiple images are then combined to produce one photograph that has an extended range of light. Shadows and Highlights are combined to enhance each, and blended to produce the end result, a photograph that you can not take with only ONE exposure.
Notice the difference in the total contrast and color range. It is amazing!