Yale University's Beinecke Rare Book & Manuscript Library features over 90,000 high resolution images of rare books and photographs, all of them readily accessible online. Tapping "Chicago" into the search field yields fascinating images of the Union Stockyards, grain elevators along the Chicago River (Anyone care for a Schlitz?), views of the lakefront as it once was, a letter from photographer Alfred Stieglitz and many more interesting documents. A Chicago history buff could lose a lot of sleep exploring it all . . .