It's the period, 1920 to 1933, when alcoholic beverages were illegal
[DOC] [TLE] Prohibition | United States history [1920-1933] | Britannica.com [PAR] Aug 11, 2016 ... ... of alcoholic beverages in the United States from 1920 to 1933 under ... (illegal, 
secretive drinking establishments), both of which were capitalized upon by 
organized crime.