Cuba Libre literally means Free Cuba, and is a cocktail first drunk by revolutionaries in the 1900s. The Andrews sisters sang about Rum and Coca Cola, and it became popular!
The drink was originally mixed in the late 1800s down south. It was the time of the Spanish-American War and the US was helping Cuba gain its freedom. The American soldiers would mix together the local rums with the newly created Coca Cola. Coca Cola first came out in 1886 and had cocaine in it, so the idea of mixing together cheap-and-interesting Coke with cheap-and-intoxicating Rum was a great one.
Even so, the popularity of Cuba Libre was pretty low key until the Andrews Sisters came along. In 1944, in the midst of World War II and soldiers looking for fun amidst the fighting, they created the song "Rum and Coca Cola". An instant hit, it popularized the island drink for the entire world. Soon Rum and Cokes were being poured in every bar.
Low carbers can of course make this drink with Diet Coke for 0g of carbs ... or try the new C2 from Coke for 12g. Of course 12g is a little high - but if you just can't wean yourself off of regular coke yet, it's a step in the right direction.
Put ice in a highball glass. Add 3 ingredients and stir. Enjoy!