Motorcycle Police on Harley-Davidsons, n.d.
Wisconsin Historical Society, Madison, Wis.
A fun Twitter account for fans of historical photos is @WIHistImages, which is run by the Wisconsin Historical Society. They and the Twitter account I mentioned last Sunday, @UWdigiCollec, frequently team up for themed Tweeting days. The week before last they did Facial Hair Friday, where both accounts posted only pictures of men with beards and mustaches, and last Tuesday they chose pictures representing the Seven Deadly Sins, in recognition of the UW football team's upcoming trip to Las Vegas.