Held from May 1 through 15, 1851, in London, England, the Great Exhibition of the Works of Industry of All Nations was the first of what would become the World’s Fair international exhibits. It was also called the Crystal Palace exhibit, because of the building in which it was held in Hyde Park. Among the many exhibits, the first weather map was displayed there, as well as the “Tempest Prognosticator,” a leech barometer invented by George Merryweather.