The Crystal Palace had the first major installation of public toilets, the "Retiring Rooms", in which sanitary engineer George Jennings installed his "Monkey Closet" flushing lavatory (initially just for men, but later catering for women also). During the exhibition, 827,280 visitors each paid one penny to use them. It is often suggested that the euphemism "spending a penny" originated at the Exhibition but the phrase is more likely to date from the 1890s when public lavatories, fitted with penny-coin-operated locks, were first established by British local authorities.