The ancient Roman kitchen was known for its advanced culinary techniques and the use of a built-in outdoor pizza oven called a 'fornax'. These ovens were made of brick or stone and were used not only for baking bread but also for cooking various dishes, including pizzas. The Romans were known for their love of flatbreads topped with various ingredients, similar to modern-day pizzas. The 'fornax' was an essential part of the Roman kitchen, allowing them to enjoy delicious and crispy pizzas cooked in an outdoor setting.