The still-young medium of photography made its debut on the world stage at the 1851 Great Exhibition, housed in the gargantuan glass and iron Crystal Palace in Hyde Park, London, and visited by six million people. At the conclusion of this first World’s Fair, the organizers commissioned a four-volume report—one of the most ambitious and consequential undertakings in the early history of photographic publishing. The production of 140 copies, each illustrated with 154 photographs, required more than 21,000 individual prints—an enormous task at a time when each photograph was “printed out” in the sun rather than “developed out” in a darkroom.