This popular hole in the wall, home to the freshest seafood around, has become an S.F. institution. Throngs of food enthusiasts pour onto the sidewalk as they wait to sit on one of the 20 stools at the narrow counter packed with oyster crackers, sliced lemon, and Tabasco. This family-run establishment opened in 1912 and has been operated by the current owners since the '40s. The owners/staff take pride in making wisecracks, being extremely efficient, and knowing both their fish and their regular customers. Try the oversize salads (shrimp, crab, prawn, or combo with Swan's signature Louie dressing), a half-dozen oysters on the half shell, and a glass of wine. Between bites, chat with your countermate and you will find that people come from all over the world to wait in line for a meal that's as close as your back yard.