A walkout basement, lower ground floor, daylight basement, English basement or terrace level is a storey that is partially underground and has a door from that level directly to the outside. Usually, 50% to 70% of the level is above ground and thus isn't a basement in the strictest sense of the word. Typical locations where such basements are built included steeply sloping lots (such as on mountains), or beneath townhouses, especially in major historical cities. Because of the windows and exterior doors that often exist on these lower levels, they're more versatile in how they can be used than cellar type basements can. In houses with walkout basements, it's common to have bedrooms and even whole apartments down there.