PROHIBITION was a period of time (1920-1933) when it was illegal to import, transport, and sell alcoholic beverages like beer, wine, and liquor. The "temperance" movement, tried to stop people from drinking alcohol.  The temperance movement began because many people believed alcohol was destroying families and causing moral corruption.
During World War I, President Woodrow Wilson ended the manufacture of alcoholic drinks to ration grain that was needed for food.  With that momentum, on January 29, 1919, the 18th Amendment was ratified making alcoholic drinks illegal in the United States. Regardless of the new law, some people continued to drink to have alcohol. People who made alcohol and smuggled it to people who wanted it were called "bootleggers." Some bootleggers produced and sold whiskey called "moonshine" or "bathtub gin." Bootleggers used modified cars to help them outrun the federal agents trying to catch them and to hide the alcohol in the body of the vehicle.
 With the Detroit River being only a mile wide in places and 28 miles long with plenty of coves and hiding places along the shoreline and among the islands such as Grosse Ile, it was a bootlegger’s dream.  These waterways carried 75% of the liquor smuggled into the United States during Prohibition.  Alcohol came over by speedy powerboats in the summer and by caravans of trucks, cars, and vans in the winter when the river became frozen enough to drive on.  Because of the very lucrative market for alcohol by Americans, it became a perfect occupation for the criminal underworld to explore.