B-52B-52 is an extremely popular cocktail that is quite easy to make. Worldwide it is known for consisting of 3 layers — coffee liqueur, creamy liqueur and orange liqueur. All the 3 are of a different density, therefore they don't mix and remain as 3 layers.
There are a few versions of how B52 appeared. Some people think it was created in a bar called Alice in Malibu and named after the bomber plane Boing B-52 Stratofortress. Some say it was first made in Keg Steakhouse bar in Calgary. But the version with Boing B-52 is leading since the name is very similar.
If you have a nice imagination, when looking at a sample of beautifully mixed B-52 you might get the association with a thermonuclear bomb that has just been dropped from B-52 plane.
Jokingly, the drinkers of this cocktail are usually called pilots, so it is acceptable if you wish your guests that are ready to try it a safe landing.