I recently came upon a website to which I am absolutely addicted. It's shorpy.com, and it features 3-4 photographs each day that are usually more than 50 years old but reprinted from an absolutely pristine and large negative (or other photographic plate). The source of these photos is mainly a large archive of photos that have been donated to the U.S. Library of Congress, and cover an enormous variety of subjects. Pictures at the site are posted in high resolution, so much so that you think you are looking at a photo that was taken very recently-- if it weren't for the subject matter. Here's such a photo of a Depression-era family living in a dugout in 1940 in Pie Town, New Mexico.
One of the great things about shorpy.com is that visitors to the site offer all sorts of information they know or are able to research about each photo. In this instance, contributors were able to find the obituary of the woman who was the girl in the left of the photo. I have already spent several hours looking at various photos and trying to find out more about the various items and people in the pictures. It sounds nerdy, but I have always had an interest in time travel, and it looks like this is the closest I'll ever get.