Civil engineering is a field of engineering that involves designing, constructing, and maintaining buildings, dams, bridges, tunnels, highways, and other structures. It uses physical laws, mathematical equations, and theories of mechanics. Civil engineering is divided into several subcategories including geotechnical engineering, structural engineering, transportation engineering, water resource engineering, environmental engineering, earthquake engineering, and urban planning. Civil engineers are responsible for planning, designing, constructing, and maintaining structures while utilizing available resources efficiently to complete projects on time and within budget, considering environmental and safety issues. The scope of civil engineering has diversified over time to include branches like structural engineering, geotechnical engineering, transportation engineering, hydraulic engineering, and environmental engineering.