You might be surprised that one of the best sandwich spots in DC is located in Union Market, where meat and produce distribution warehouses seem to outnumber people. A. Litteri was opened in 1926 and served as a wholesaler until 1988, when the family-owned spot made the switch to retail and began stocking Italian groceries. Today, the packed-like-sardines shelves swell with olive oil, roasted red peppers, pastas, vinegars, and a dizzying maze of imported wines. A. Litteri is best known for its deli counter, where sandwiches, soups, pizzas, and pasta dishes attract a diverse, loyal lunch crowd. The most common order? An Italian sub with all the fix-ins, from ham, mortadella, Genoa salami, and capicola to Swiss, mozzarella, pickles, and peppers.