Sometimes referred to as the heart of the home, the kitchen is a place to prepare and cook food and, depending on the size, can be used to eat and entertain guests. In Ancient Greek homes, this room was a central open air patio but it was not until around 1800 that the stove, which enclosed fire completely, made cooking indoors possible. As technology advances, so do kitchens' design and efficiency. The introduction of the kitchen island has lent more flexibility to the positioning of the kitchen cabinets and kitchen sink, and helped make open plan kitchens and dining rooms a reality.