 Finally linked to the rest of the nation by rail , Denver prospered as a service and supply center . The young city grew during these years , attracting millionaires with their mansions , as well as the poverty and crime of a rapidly growing city . Denver citizens were proud when the rich chose Denver and were thrilled that Horace Tabor , the Leadville mining millionaire , built an impressive business block at 16th and Larimer as well as the elegant Tabor Grand Opera House . Luxurious hotels , including the much @-@ loved Brown Palace Hotel , soon followed , as well as splendid homes for millionaires like the Croke , Patterson , Campbell Mansion at 11th and Pennsylvania and the now @-@ demolished Moffat Mansion at 8th and Grant . Intent on transforming Denver into one of the world 's great cities , leaders wooed industry and enticed laborers to work in these factories . Soon , in addition to the elite and a large middle class , Denver had a growing population of German , Italian , and Chinese laborers , soon followed by African @-@ Americans and Spanish @-@ surname workers . Unprepared for this influx , the Silver Crash of 1893 unsettled political , social , and economic balances , laying the foundation for ethnic bigotry , such as the Red Scare and the rise of the Ku Klux Klan , as well as corruption and crime . 
