In its basic form, a pizza (alternatively pizza pie) is an oven-baked flat, usually circular bread covered with various toppings and baked. The usual toppings are cheese and a tomato-based sauce. The cheese is usually mozzarella or its commercial substitute, pizza cheese. Various other foodstuffs can be added to this design, most typically processed meats such as salami and pepperoni, ham and also vegetables such as sweet bell-peppers (of the capsicum family), and mushrooms.
In recent years a trend towards "gourmet pizza" has emerged in various places, notably in Europe, Oceania and Asia. These pizzas consist of the same basic design, but include an exceptionally diverse choice of ingredients, such as egg, pineapple, eggplant, lamb, couscous, chicken, fish and shell-fish, meats done in ethnic styles such as Morroccan lamb and non-traditional spices such as curry and Thai sweet chili. A "white pizza" uses no tomato sauce, often substituting pesto sauce.
The pizza originated in Naples, but it became a popular meal item in America in the early 20th century. Since then it has spread throughout the world. Several major corporations are chiefly engaged in the commercial production of pizza, notably Pizza Hut (owned by Pepsi-Cola) and Dominos Pizza.
Pizza may be baked with thin bread bottom (Italian style) or with thicker bread (pan pizza).