The Crystal Palace's large expanses of glass turned sunlight into heat necessitating an extensive system of louvers for cooling and ventilation. The louvers are located in the top 3 feet of the wall panels on each floor and the bottom 4 1/2 feet of the wall panels on the ground floor (fig. 1). Long runs of louvers were actuated with a wheel and gear mechanism. With this system, one person could open all of the building's louvers in a short time (fig. 2). The floor works in conjunction with the louvers to provide ventilation by passing air through gaps between the floor planks. Air under the building is not exposed to the sun and is cooler than the air in the crowded building. The area of the open louvers is larger than the area of the floor slots, creating suction and drawing the cool air up through the floor and forcing the hot air up and out the wall louvers (fig. 3).