The term A-frame design refers to a building or home design that features a steeply peaked roofline with a ceiling that opens to the top rafters. The exterior style of such a house often also has a high-peaked roof in the shape of the letter A. The A-frame design reached its height of popularity in the mid 20th century, rising to prominence in the 1950s and declining in use the 1970s. The roof of the building usually begins at the foundation line or a few feet above the ground. The building is often oriented with windows facing a particular view, such as a body of water or mountains. The steeply pitched roof is the dominant architectural feature. In some A-frame houses, two stories occupy the space under the roof, with a big open living space below, and a loft space or bedroom space above.