I learned, from a high school student who did his senior project on photography, that the first thing our eyes go to is color. When we take away color, we look at tones and shadows. It's quite apparent looking at these photos. Thanks for sharing.
I've seen several variations of this, unfortunately this one doesn't feature the b&w original for all of them. I think that almost without exception I prefer the originals.
http://twentytwowords.com/2013/11/06/realistically-colorized-historical-photos-make-the-past-seem-incredibly-real-36-pictures/
Sarah