The Underground is a fun bar at The Mob Museum. My husband and I sat at the bar and the service was great. Our bartender was attentive and the drinks we ordered were really good. I started with The Underground Old Fashioned, which comes in a bottle hidden in a book! I also had a Manhattan (one of the best I've ever had), and my husband had gin martinis, which he said were delicious. The decor in the bar is really cute and there are museum artifacts throughout. We went on Saturday night and the live jazz music was just right. My only complaint is that drinks were very pricey, even for Vegas standards ($68 pre-tip for 4 cocktails). This will definitely be a fun place to bring family and friends when they come to visit Vegas.