Why are we laughing? Researchers are asking this question, and have come up with several ideas, if no absolute answers. Are they all wet or on the right track?

Old Hollywood Movie Stills. High quality images too.

WWI Image Archive 'EarlyAviator': Large collection concentrating on air-ware. Includes airships, guns, planes, posters/paintings/badges & death photos. The site could use a makeover with thumbs but compensates with content over appearance. [The death section is pretty benign - nothing gruesome to my mind - mostly crash scenes/graves.]