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A bed is a piece of furniture which is used as a place to sleep or relax.
Most modern beds consist of a soft, cushioned mattress on a bed frame, the mattress resting either on a solid base, often wood slats, or a sprung base. Many beds include a box spring inner-sprung base, which is a large mattress-sized box containing wood and springs that provide additional support and suspension for the mattress. Beds are available in many sizes, ranging from infant-sized bassinets and cribs, to small beds for a single person or adult, to large queen and king-size beds designed for two people. While most beds are single mattresses on a fixed frame, there are other varieties, such as the murphy bed, which folds into a wall, the sofa bed, which folds out of a sofa, and the bunk bed, which provides two mattresses on two tiers. Temporary beds include the inflatable air mattress and the folding camp cot. Some beds contain neither a padded mattress nor a bed frame, such as the hammock, which is considered one of the most comfortable places to rest while swaying side to side. Some beds are made especially for animals.
Beds may have a headboard for resting against, and may have side rails and footboards. "Headboard only" beds may incorporate a "dust ruffle", "bed skirt", or "valance sheet" to hide the bed frame. To support the head, a pillow made of a soft, padded material is usually placed on the top of the mattress. Some form of covering blanket is often used to insulate the sleeper, often bed sheets, a quilt, or a duvet, collectively referred to as bedding. Bedding is the removable non-furniture portion of a bed, which enables these components to be washed or aired out.
Early beds were little more than piles of straw or some other natural material. An important change was raising them off the ground, to avoid drafts, dirt, and pests. 23-5 million years ago, before the advent of humans, apes began creating beds composed of a sleeping platform including a wooden pillow. Bedding dated around to 3600 BC was discovered in Sibudu Cave, South Africa. The bedding consists of sedge and other monocotyledons topped with the leaves of Cryptocarya woodii Engl. Beds found in a preserved northern Scottish village, which were raised boxes made of stone and likely topped with comfortable fillers, were dated to between 3200 BC and 2200 BC. The Egyptians had high bedsteads which were ascended by steps, with bolsters or pillows, and curtains to hang around. The elite of Egyptian society such as its pharaohs and queens even had beds made of wood, sometimes gilded. Often there was a head-rest as well, semi-cylindrical and made of stone, wood, or metal. Ancient Assyrians, Medes, and Persians had beds of a similar kind, and frequently decorated their furniture with inlays or appliques of metal, mother-of-pearl, and ivory.