The Rosedale Arch is one monument that has a nice location, one that has a great view of the Kansas City skyline. It can also be seen from I-35, the 35th Division Memorial Highway, and probably more so now that the leaves are falling from the trees.
This link goes to a page that has a pretty good description of the arch, so instead of repeating the story: http://www.kansastravel.org/kansascitykansas/rosedalearch.htm