A few months ago, courtesy of Bryan, I stumbled on a link to this archive of colour photographs taken by photographers of the Farm Security Administration/Office of War Information from Depression-era America (apparently it's a fairly well-known internet resource). I remember seeing a few people's reaction to these images on Facebook including one commenter who was bothered by the use of colour, saying that it somehow felt wrong for the subject matter.
I was intrigued by this comment, because I had almost precisely the opposite reaction. This is the first time that I have seen colour photographs from this period in US history, but like anyone interested in photography, I have seen my fair share of black-and-white images from the Depression years. That period is so intrinsically and deeply associated with black-and-white that I found it shocking to see just how colorful this time actually was. These photographs made me feel like my conception of these years was all wrong.
Subconsciously I had almost come to assume that the world actually was black-and-white during these years: it seems so appropriate for photographs documenting difficult and dark years like these to be totally drained of colour. I realise that this about as basic a eureka moment as you can get with photography ("Wow, look, things seem really different in colour than in black-and-white"), but when a time becomes so characterised by a particular kind of photograph, you can't help but be taken aback when seeing it depicted in an entirely different way.
You can see a fuller selection of images from this archive on the Library of Congress Flickr page.