The beauty of the internet is found in things like this. You can access the archive of all photographs taken by/for the government for free. One of the most famous photographs that most people know is Dorothea Lange's "Migrant Mother".
This forlorn look at the desperation of the dust bowl has captivated viewers forever. However, did you know that it was created as a service for the United States government? During the great depression tons of photographers were hired to document life around the United States. All of that imagery is available to you for free! You can access the original negatives, high resolution scans, now for free.