Archaeologists have found bricks in the Middle East dating 10,000 years ago. Scientists suggest that these bricks were made from mud left after the rivers in that area flooded. The bricks were molded by hand and left in the sun to dry. Structures were built by layering the bricks using mud and tar as mortar. The ancient city of Ur (modern Iraq) was built with mud bricks around 4,000 B.C. The Bible (Exodus 1:14; 5:4-19) provides the earliest written documentation of brick production—the Israelites made bricks for their Egyptian rulers. These bricks were made of clay dug from the earth, mixed with straw, and baked in crude ovens or burned in a fire. Many ancient structures made of bricks, such as the Great Wall of China and remnants of Roman buildings, are still standing today. The Romans further developed kiln-baked bricks and spread the art of brickmaking throughout Europe.
The oldest type of brick in the Western Hemisphere is the adobe brick. Adobe bricks are made from adobe soil, comprised of clay, quartz, and other minerals, and baked in the sun. Adobe soil can be found in dry regions throughout the world, but most notably in Central America, Mexico, and the southwestern United States. The Pyramid of the Sun was built of adobe bricks by the Aztecs in the fifteenth century and is still standing. In North America, bricks were used as early as the seventeenth century. Bricks were used extensively for building new factories and homes during the Industrial Revolution. Until the nineteenth century, raw materials for bricks were mined and mixed, and bricks were formed, by manual labor. The first brickmaking machines were steam powered, and the bricks were fired with wood or coal as fuel. Modern brickmaking equipment is powered bygas and electricity. Some manufacturers still produce bricks by hand, but the majority are machine made.