Ernest Hemingway's favorite bar in Havana, La Bodeguita Del Medio is located a block off Plaza de la Catedral and near the hotel where Hemingway often stayed. When it gets busy they only make mojitos, and the bartender shown here is putting mint leaves in a long line of glasses where he's making the rum-based drink.
Hemingway also frequented a bar in Centro Habana called El Floridita, where he usually drank daiquiris, hence the sign behind the bartender. Both places can be crowded with tourists in the evening, so early afternoon is best if you want to get a seat.