Transportation and construction along with their upstream manufacturing supply businesses have been the bulk of heavy industry throughout the industrial age, along with some capital-intensive manufacturing. Traditional examples from the mid-19th century through the early 20th included steelmaking, artillery production, locomotive erection, machine tool building, and the heavier types of mining. From the late 19th century through the mid-20th, as the chemical industry and electrical industry developed, they involved components of both heavy industry and light industry, which was soon also true for the automotive industry and the aircraft industry. Modern shipbuilding (since steel replaced wood) is considered heavy industry. Large systems are often characteristic of heavy industry such as the construction of skyscrapers and large dams during the post–World War II era, and the manufacture/deployment of large rockets and giant wind turbines through the 21st century.