The Crystal Palace was a cast-iron and plate-glass structure originally built in Hyde Park, London, to house the Great Exhibition of 1851. More than 14,000 exhibitors from around the world gathered in its 990,000-square-foot (92,000 m2) exhibition space to display examples of technology developed in the Industrial Revolution. Designed by Joseph Paxton, the Great Exhibition building was 1,851 feet (564 m) long, with an interior height of 128 feet (39 m). The invention of the cast plate glass method in 1848 made possible the production of large sheets of cheap but strong glass, and its use in the Crystal Palace created a structure with the greatest area of glass ever seen in a building and astonished visitors with its clear walls and ceilings that did not require interior lights.