Engineering, applied science devoted to the design and construction of machinery and transportation and communications networks. Engineering is divided into many specialties (aeronautical, civil, chemical, electrical, mechanical, and so on), though the branches naturally overlap. The Engineers' Council for Professional Development, formed in 1932, recognizes 25 different branches. Until the 19th century, the term engineer signified a military engineer, responsible for fortifications, tunnels, and explosives, or a civil engineer, responsible for designing and building such structures as dams and bridges. The industrial revolution, however, opened up the fields of mechanical, chemical, and electrical engineering. The entry to engineering may be a 3-year or longer course at a university, engineering school, or technical institute, followed by practical experience in working on actual projects.