The St. Valentine's Day Massacre
Over the last 96 years, the escapades of Al Capone, Chicago's legendary gangster and mob boss, became inescapably entangled with the legends and lore of Route 66. After all, Capone rose to fame or infamy during the mid-1920s, and U.S. Highway 66 was born as part of the federal numbered highway system in 1926. But more importantly, Chicago was the designated original eastern terminus (at Jackson Boulevard and South Michigan Avenue) of Route 66, and the City of Chicago was Capone's adopted home city. Sitings of Capone and his associates were commonplace along the length of Illinois' highways, especially between Chicago and St. Louis, during the Prohibition years (1920-1933).
Illegal booze manufactured in carefully-hidden stills ruled the underworld and made deadly enemies of rival gangs. The SMC Cartage Company garage at 2122 Clark Street in Chicago stood three miles north of Route 66, but the horrific event that took place there on Valentine's Day in 1929 became part of the Capone saga, forever tying it to the stories of crime and murder that make up the seamy side of Route 66's legends and lore.
Capone, born and raised in Brooklyn, came to Chicago in 1920, and found work as a bouncer. It wouldn't take many years before his name was instantly recognized and associated with booze, crime, and violence. Scarface, his nickname due to a knife fight's lasting scars on his face, became the most infamous gangster and mob boss in America. It didn't take long after Prohibition began in January 1920 before multiple gangs in Chicago began working the illegal alcohol trade as their primary business.
Turf wars were common between Capone's Italian South Side gang and George Bugs Moran's Irish North Side gang. As they remained locked in a gang war for control of the city's bootlegging rackets, shootings were common. But what happened on Valentine's Day in 1929 in Chicago added a sickening dimension to the gangster modus operandi, making headlines around the world, lessening Chicago's tolerance for illegal liquor rackets, and inspiring the FBI to significantly increase their force.
https://www.riverbender.com/articles/details/the-st-valentines-day-massacre-56602.cfm