Mudbrick was used for the construction of Elamiteziggurats--some of the world's largest and oldest constructions. Choqa Zanbil, a 13th-century BC ziggurat in Iran, is similarly constructed from clay bricks combined with burnt bricks.
A mudbrick or mud-brick is an air-dried brick, made of a mixture of loam, mud, sand and water mixed with a binding material such as rice husks or straw. Though mudbricks are known from 7000 to 6000 BCE, since 4000 BC, bricks have also been fired, to increase their strength and durability.
In warm regions with very little timber available to fuel a kiln, bricks were generally sun-dried. In some cases, brickmakers extended the life of mud bricks by putting fired bricks on top or covering them with stucco.
Mud-brick stamped with seal impression of raised relief of the Treasury of the Vizier. From Lahun, Fayum, Egypt. 12th Dynasty. The Petrie Museum of Egyptian Archaeology, London
Mudbricks were adopted in the Middle East from Indus Valley Cities during the Pre-Pottery Neolithic B period. The Mesopotamians used sun-dried bricks in their city construction;  typically these bricks were flat on the bottom and curved on the top, called plano-convex mud bricks. Some were formed in a square mould and rounded so that the middle was thicker than the ends.
In Ancient Egypt, workers gathered mud from the Nile river and poured it into a pit. Workers then tramped on the mud while straw was added to solidify the mold. The mudbricks were chemically suitable as fertilizer, leading to the destruction of many ancient Egyptian ruins, such as at Edfu. A well-preserved site is Amarna. Mudbrick use increased at the time of Roman influence.
In areas of Spanish influence, mud-brick construction is called adobe, and developed over time into a complete system of wall protection, flat roofing and finishes which in modern English usage is often referred to as adobe style, regardless of the construction method.
The Great Mosque of Djenné is a well-known Mosque located in Djenné, Mali, and the largest mudbrick structure in the world.
The Great Mosque of Djenné, in central Mali, is the world's largest mudbrick structure. It, like much Sahelian architecture, is built with a mudbrick called Banco, a recipe of mud and grain husks, fermented, and either formed into bricks or applied on surfaces as a plaster like paste in broad strokes. This plaster must be reapplied annually.
Mudbrick architecture worldwide
Production of mudbricks for construction in Niger, 2007.
EARTHA: Earth Architecture and Conservation in East Anglia, British organisation that focuses on the proper maintenance and conservation of earth buildings in a region of the UK that has a long history of building with mud. Very experienced experts are contactable and there are regular demonstrations in the area.