In the US National Absinthe Day takes place on March 05, 2018. This day should only be celebrated by those who are 21 or older, since the alcohol content of absinthe can be up to 90 percent. However, typical values are 45 to 78 percent. Most absinthe is diluted with water to drink, which is also recommended on Absinthe Day.
Since absinthe almost always has a green color, it is colloquially referred to as the "Green Fairy". Absinthe is liquor consisting of vermouth, fennel, anise, and other herbs. Who brought up the idea of National Absinthe Day, unfortunately, is unclear.