There's an interesting article on photographer Richard Avedon in a recent NY Times. It is focused on (no pun intended) his wall size portraits made in the late 60's and early 70's (that would be the 20th century). You can find it at this LINK. I find this work to be both artistic and of historical significance. Of course good art through the centuries has been of historical significance - not just as being "good art" from a certain era, but on what it tells us about the times in which it was created. This is what I mean here.