The muffuletta was supposedly created by the Central Grocery for the Italian fruit and vegetable vendors in the French Market.  Like the Earl of Sandwich story, it served as a meal-between-bread that was portable, and could be easily eaten while still attending to their wares.  It starts with a marinated olive salad, made with sliced green and black olives, chopped celery, cauliflower, and carrot, lots of garlic, oregano, olive oil and vinegar.
 
There is a loaf made for this, it’s a large, seeded bun (about 10″ in diameter) cut in half horizontally, some of the inner dough pulled out a little to form a pocket for adding olive salad, and slices of mortadella, salami, ham, and provolone (there are other meat combinations but these are the most traditional).  It’s sold whole or in half, and depending if you want to share, when you cut it, you end up with a thick, wedged shaped sandwich. 
 
Purists will tell you the muffuletta should always be served at room temperature and never heated, but I am a little partial to the Napoleon Houses’ muf where their’s are toasted, and the cheese melts a little.
 
curds – someone tell me about them