large concrete or cement masonry units for building
Concrete masonry unit Those that use cinders (fly ash or bottom ash) are called cinder blocks in North America, breeze blocks (breeze is a synonym of ash)[1] in the United Kingdom, and hollow blocks in the Philippines. In New Zealand they are known as concrete blocks or more commonly as just blocks. In Australia they are also known as Besser blocks or Besser bricks, because the American-based Besser Company was a major supplier of concrete-block-making machinery. Clinker blocks use clinker as aggregate. In non-technical usage, the terms cinder block and breeze block are often generalized to cover all of these varieties.
Wall of Jericho The Neolithic wall was complemented by a stone tower built into it. The wall was possibly built in order to prevent floods and the tower used for ceremonial purposes[7] but the height of the wall (approximately 1.5 to 2 metres (4.9 to 6.6 ft)[8] thick and 3.7 to 5.2 metres (12 to 17 ft) high, as well as that of the tower (8.5 metres (28 ft)) suggests a defensive purpose as well. Furthermore, the construction of such a project implies some sort of social organization, division of labour, and classes. Surrounding the wall was a ditch 8.2 metres (27 ft) wide by 2.7 metres (9 ft) deep, cut through solid bedrock with a circumference around the town of as much as 600 metres (2,000 ft).[9] Kathleen Kenyon commented on the work involved in the construction of the ditch: "The labor involved in excavating this ditch out of solid rock must have been tremendous. As we have discovered nothing in the way of heavy flint picks, one can only suppose that it was carried out with stone mauls, perhaps helped by splitting with fire and water."[10]