Dolmens are megalithic structures that consist of a large capstone or capstones supported by a number of smaller upright stones, creating an enclosed chamber area. They are found in many parts of the world, including northwest Europe, southern Scandinavia, Britain, Ireland, the Low Countries, central and southern Europe, the Iberian Peninsula, Switzerland, Italy, and islands in the Mediterranean. Archaeologists believe that dolmens were primarily used as burial chambers for important people within a community, and bones have been found beneath some dolmens confirming that they were in fact burial chambers. However, it remains unclear when, why, and by whom the earliest dolmens were made, and they are generally all regarded as tombs or burial chambers, despite the absence of clear evidence for this. Some dolmens were clearly incorporated into large mounds of earth and stone, but in other areas, the stone chambers were open to the elements, albeit sometimes enclosed by a small knee-high area of stones. That stone enclosure may have been built to reduce ease of access to the chamber by setting aside the immediate area as sacred.