America's oldest restaurant in continuous service, the Union Oyster House opened in 1826, and the booths and oyster bar haven't moved since. The food is tasty, traditional New England fare, popular with visitors walking on the adjacent Freedom Trail and savvy locals. They're not looking for anything fancy, and you shouldn't, either -- simple, classic preparations account for the restaurant's staying power. At the crescent-shaped bar on the lower level of the cramped, low-ceilinged building (a National Historic Landmark "where Daniel Webster drank many a toddy in his day"), try oyster stew or the cold seafood sampler of oysters, clams, and shrimp to start. Follow with a broiled or grilled dish such as scrod or salmon, or perhaps fried seafood or grilled pork loin. A "shore dinner" of chowder, steamers or mussels, lobster, corn, potatoes, and dessert is an excellent introduction to local favorites. For dessert, try gingerbread with whipped cream. Tip: A plaque marks John F. Kennedy's favorite booth (no. 18), where he often sat to read the Sunday papers.