You can also use twist to get a nice overhang effect.  Create a terrain.  Make it high for the parts that will overhang.  With the terrain selected, click the Numerics tab.  The second icon from the bottom is Twist.  Just grab the Z=>Y or Z=>X arrow point and give it a good pull.  The trick to this is you get one chance - don't try to twist it again - the whole terrain will screw up.  You can undo it and try again...  It take a few trys to get a good look, but it really does work fine.

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