July 11 is National Free Slurpee Day!.
The Slurpee was invented by Omar Knedlik in 1959 - by accident.
The Kansas City Dairy Queen owner's machines often malfunctioned, so he put his sodas in the freezer instead.
When he served them to customers, they were partially frozen, but his customers weren't mad at all.
They loved the half-ice, half-fizzy mixture so much that Knedlik started selling them, branded ICEE.
As the drink got more popular, its production was standardized, and in 1965 it caught the eyes of 7-Eleven.
They licensed Knedlik's drink and rebranded it "Slurpee," based on the sound its drinkers made while enjoying the treat.
Its popularity exploded and the ensuing
years saw dozens of themed cups and new flavors. .
7-Eleven celebrated its first National Free Slurpee Day in 2002
