A bed base, sometimes called a foundation, is the part of a bed that supports the mattress. The bed base can itself be held in place and framed by the bedstead. In the United States, box-spring bed bases are very common. In Europe, sprung slats are much more common.
A bed base
An iCansi sleeping mat is often made of iNcume (a species of rush). Mtonjaneni Zulu Historical Museum, northern KwaZulu-Natal
Self-inflating camping mat, filled with rebounding foam
Each of these futon beds has three mattresses and a sheet-covered duvet, stacked directly on the tatami-matted floor. Japan
A bed is an item of furniture that is used as a place to sleep, rest, and relax.
Bedroom on the Detmold Open-air Museum premises
Modern day beds
Tutankhamun's gilded bed from the 14th century BC, a bier from his tomb, fashioned to resemble the goddess Sekhmet, the fierce lioness who was the protector of the kings in life and death, Cairo Museum
These stone boxes in Skara Brae are thought to have held bedding. The stone-built settlement was inhabited between c. 3180 BC to about c. 2500 BC