Union Oyster House.
The Oldest Running Restaurant in the whole USA.
Mad expensive, but not that bad if you share stuff with a few people.
Best clam chowder easily, and definitely the most delicious Lobster Ravioli. Great for seafood.
Mussels Basque Style ($12.95) - Steamed with garlic and white wine, comes with two pieces of garlic bread.
Oyster House Clam Chowder - Bowl ($7.95)
Lobster Ravioli in lobster cream with sherry and fresh herbs ($14.95) - comes with four pieces if you order it as an appetizer.