Greeks, multi-talented individuals that they often are, have a long tradition of distilling.
Over the millennium Greeks learned how to make all kinds of spirits and today certain unscrupulous bar owners and public officials and police look the other way as these same individuals supply many bars and clubs with Bomba or counterfeit booze.
Bomba is locally distilled moonshine type alcohol made to resemble expensive branded Vodka, Scotch, Gin. Your favorite brand!.
Its whipped up with God knows what in it and then blithely poured into empty bottles of higher quality liquor and then poured as the real thing at the corresponding higher price.
Scoff if you must at 'Bomba' but many know better. The problem of Bomba isn't just in Athens, its all over Greece and in Santorini and Mykonos and other hot spots too. So be careful when you order a high quality cocktail and try, if you can to make sure its the real thing.
Better sill go Greek and order a tsipouro, raki or ouzo. Many islands have their own bottled liquors which can pleasantly surprise you.