Pittsburgh is a city located in Pennsylvania, the U.S. This city is well known for the three rivers (the Allegheny, Monongahela and Ohio) that flow here. In Pittsburgh, the steel industry developed rapidly after 1830 and a milestone in the steel production was achieved in the year 1875 when a new process called Bessemer process was introduced by Edgar Thomson Works to produce steel. Very soon Pittsburgh became the steel capital of the world.
