Mud-brick, also known as adobe, has been a popular material for construction for thousands of years. It is a mixture of mud, straw and water, often formed into rectangular shapes and dried in the sun. Synonyms for mud-brick include cob, sun-dried brick, earth block, and rammed earth. Cob is a similar material made from a mixture of mud and straw, but it is often applied by hand to create rounded, organic shapes. Sun-dried brick is widely used in India and other parts of the world, and is made by mixing mud and water and then shaping the bricks before leaving them to dry in the sun. Earth blocks and rammed earth are both variations of mud-brick that are typically compressed using machinery to create a denser material.