Civil engineering is the discipline that deals with both the natural and artificial physical environment. This field is one that designs, constructs, and maintains bridges, roads, dams, pipelines, railways, and the likes. The field of civil engineering is considered to be the second oldest engineering discipline in the world, after military engineering. Thus the name is believed to derive from this distinction. There are many sub-categories under the field including construction engineering, environmental engineering, forensic engineering, geotechnical engineering, structural engineering, surveying, urban engineering, water resources engineering, and transportation engineering.