The civil engineer may focus in environmental control and in the development or redevelopment of a geographic area through overall planning, as well as in the design, construction, and operation of structures and facilities for public and private use. Included in the broad field of civil engineering are the following: buildings, bridges, and industrial installations, soil mechanics and foundations, transportation, including highways, traffic, airports, and harbors, hydraulic engineering, including irrigation, water resources, including power plants and dams, water supply, waste disposal, air pollution, hazardous and solid wastes, and environmental sanitation. Modern-day requirements have necessitated involvement in the medical and dental fields, oceanography, polar exploration, energy resources, and the space effort.