Civil engineers design and plan massive infrastructure projects, including roadways and airports. Other large-scale construction projects that they may oversee, include buildings, tunnels, bridges, dams, and sewage treatment and water supply systems. They have to assess the feasibility of plans in regards to safety concerns and financial costs, and they often work directly with regional and urban planners. Ultimately, civil engineers are charged with managing the design and implementation of the infrastructure for a project. They lead construction managers, civil engineering technicians, surveyors, and other professionals to execute their plans and ensure that projects comply with regulations. As a subset of civil engineering, geotechnical engineers investigate and analyze what lies beneath the earth’s surface.