Civil engineers create, improve and protect the environment in which we live. They plan, design and oversee construction and maintenance of building structures and infrastructure, such as roads, railways, airports, bridges, harbours, dams, irrigation projects, power plants, and water and sewerage systems. Civil engineers plan, design, and supervise the construction and maintenance of building and infrastructure projects. These projects may include facilities, bridges, roads, tunnels, and water and sewage systems. Civil engineers design, construct, manage and maintain the infrastructure of modern society. Roads, railways, tunnels, buildings, bridges, airports, mines, dams, ports and harbours, water supply and sewerage systems and flood mitigation works are all shaped by civil engineers.