I think these speak for themselves, but while Mount Rushmore is well known and the monumental scale is probably no surprise given its frequent appearance on movie screens, Crazy Horse is less well known but I think, more spectacular. I hope you can see the relative size of the machinery! If you are ever in South Dakota do take in both, you will be blown away by the scale.
I hope you like the illusion of distance and scale as interesting as I do. Plane coming into land at San Diego.