Concrete blocks, also known as concrete masonry units (CMUs), are rectangular blocks made from a mixture of cement, water, and aggregates like sand or gravel. They are commonly used in construction for building walls, foundations, and other structures due to their strength and durability. Concrete blocks can be solid or hollow, with hollow blocks often used for insulation and reducing weight. These blocks come in various sizes and shapes, allowing for flexibility in design. They are fire-resistant, pest-resistant, and can withstand harsh weather conditions, making them a popular choice for both residential and commercial buildings. Additionally, concrete blocks can be easily cut or shaped to fit specific construction needs.