Who was the most famous crime boss gangster of the 1920's?

Al "Scarface" Capone is one of the most famous gangsters in American history. He began his notorious career by establishing speakeasies in Chicago during the Prohibition era. Over the years, he also began to control gambling and prostitution during the 1920's. In 1931, he was found guilty for evasion of tax payments and was sentenced to 11 years in prison.