Back in the old days like in the 1930s, most people in the world had no idea what pizza was. In some of the Italian communities in America, pizza was found but I've heard that non Italians thought it was a strange food and I imagine many of them probably refused to eat this new weird food. Later in the 1960s, Pizza Hut and Dominos Pizza began to expand their business. After a few more decades, it came to the point that pizza was known all over America. In recent decades, just about every American had heard of pizza and even tried it so pizza unfamiliarity declined.