Ask yourself: 1) Are you amused and/or pleased by kitsch? 2) Are you untroubled by mystery? 3) Do you like rum? If you answered yes to all three, you MUST have a cocktail at this tiki bar. The delightfully cheesy joint has been in the same location just off Puerta del Sol for 45 years and extends about three floors underground. Once seated in what looks like a sea cave, you'll find that the menu shows only drink names, prices, and the type of glass each beverage is served in. You can ask the server to name the ingredients, but where's the fun in that? Upon ordering, your table will be covered with complementary bar snacks that include olives, potato chips, fried corn, peanuts, and a ham sandwich on buttered white bread with no crust. The music is a mix of 80s, Hawaiian, and now; the straws are absurdly long (all the better for sneaking a sip from friend's glass); the sandwich makes no sense. All this is to say Mauna Loa is the perfect escape from thousands of people scurrying to and from Plaza Mayor on the streets above the bar.