Denver's economy before 1870 had been rooted in mining; it then grew by expanding its role in railroads, wholesale trade, manufacturing, food processing, and servicing the growing agricultural and ranching hinterland. Between 1870 and 1890, manufacturing output soared from $600,000 to $40 million, and the population grew by a factor of 20 times to 107,000. Denver had always attracted miners, workers, whores, and travelers. Saloons and gambling dens sprung up overnight. The city fathers boasted of its fine theaters, and especially the Tabor Grand Opera House built in 1881. By 1890, Denver had grown to be the 26th largest city in America, and the fifth-largest city west of the Mississippi River. The boom times attracted millionaires and their mansions, as well as hustlers, poverty, and crime. Denver gained regional notoriety with its range of bawdy houses, from the sumptuous quarters of renowned madams to the squalid "cribs" located a few blocks away. Business was good; visitors spent lavishly, then left town. As long as madams conducted their business discreetly, and "crib girls" did not advertise their availability too crudely, authorities took their bribes and looked the other way. Occasional cleanups and crack downs satisfied the demands for reform.