I've been to Arlington a few times, have some kin buried there as well. When you leave the visitor center and walk down the main walk that soon splits off into many paths, there's a HUGE McDonald's-esque grave marker on the right. Belongs to Robert S. McNamara, the reason so many of the other markers exist. Contrast that to John McCain's father, a retired admiral, small nondescript marker that could have belonged to one of his orderlies