A loggia is a room, hall, gallery, or porch having one or more sides exposed to the air; it arose in the Mediterranean region, where an open sitting room with sun protection was desired. A loggia on the roof of an ancient Egyptian home, or an internal loggia facing a court, was common. The word is also used for such rooms today. Loggias are found all over Italy, especially in Tuscany and Umbria. They are particularly abundant in Pienza, where they can be seen in several buildings including Palazzo Piccolomini, which has two separate loggias. Loggias were introduced to Europe by Arab builders in the 11th century. Originally they were used as outdoor smoking rooms, but eventually they became part of houses. Today they are used as living rooms in warm climates or as additional bedrooms when needed. Some house museums in Europe have displayed their rooms as if they were original builder's plans. These rooms with false ceilings are called "hypocausts" because they were originally built with heating systems based on hot air flowing through porous rocks (today's hypocausts use heat pumps instead). In addition to being a place to enjoy the sunshine, sit out on cold days, or receive guests, loggias are often decorated with paintings, sculptures, or stained-glass windows by famous artists. Some have murals by modern artists too!