Washington DC: The Old & the New

One thing I notice walking around Washington Dc is how many old buildings there are right next to new buildings. When I say old I mean buildings constructed from the late 19th centrury to the early 20th, and when I say new buildings I mean those constructed around mid 20th century and onward.
I thought it would be a great idea to photograph these buildings and show everybody that great cities like Washington DC and other cities is basically a mixture of old and new: