Ah, yes, lining up a peak silhouette with the sun probably wouldn't be a good idea IRL (OUCH!). This was an extreme example (the pics were to answer a question on another forum). Here is another series of shots showing those effects, and how the total final effect changes depending on elevation and thus view angle:









The extreme shadowing in the last shot is an example of the Unreal3 engine 'compensating' for not being able to actually achieve the real light intensity from the sun, so the engine fakes what your eye would do when confronting that situation, by simulating the sensory contrast effects that happen with physical light. Real-time engines these days, right?