The Grand Canyon isn't just one of Arizona's greatest monuments. Heck, it's not even one of America's greatest, but one of the most jaw dropping locations on planet Earth.
There is no greater American monument to the natural world than the Grand Canyon. The massive hole in the ground stretches over a million acres and draws in millions of visitors every year.
In terms of states with the most natural beauty, I'd throw Arizona at the top of the list. Every inch of this state is covered in some of the most awe-inspiring views known to man.