New England Style Chowder is cream-based and uses potatoes, onions, celery, and clams. Manhattan Style Chowder has a tomato broth base and in addition to the potatoes, onion, and celery, it might have green peppers and carrots. And last but not least, you have your Rhode Island Clam Chowder, which has a thin broth base that may or may not involve tomato sauce.  It includes the same kinds of vegetables but uses quahog clams instead of the classic clams you can buy in a can. And all three chowders can have bacon in them because…bacon.