Step 1 : Introduction to the question "Drugstore chain Walgreens blossomed in the 1920s thanks to which event?"
...Manufacturing, selling, and transporting “intoxicating liquors” was made illegal during the American Prohibition period from 1920 to 1933. However, it was legal to drink alcohol, if you could somehow find it. Pharmacies got creative by selling alcoholic drinks under the guise of a “medicinal treatment” for things like toothaches. The drugstore chain Walgreens saw explosive growth, expanding from 20 locations to more than 500 during the 1920s.