At the heart of the Cosmopolitan Hotel, next to the great chandelier hall, is Holsteins. This Burger Bar in Mandalay Bay is the world-wide reference in hamburgers, but it's also fashionable. These serve specialty burgers, with premium ingredients, and their prices are in accordance to their quality. I really recommend it, and the shakes are wonderful, simply wonderful! The music was great, though it would be better if it wasn't so loud.