Pittsburgh, Pennsylvania is in the south western corner of Pennsylvania, in the USA. Andrew Carnegie of Scotland built his steel empire here. Pittsburgh was also the home of Henry Clay Frick, the Mellons, the Heinz's of Heinz ketchup. In the mid 1900's the air was black with smoke from blast furnaces at the many steel mills. Since then Pittsburgh has gone through a rebirth and clean up, and today is a beautiful city with an impressive skyline and many bridges.
The American steel industry created an economic boom that made this country relevant for international trade. It also created an American middle class. New York's skyscrapers were built with Pittsburgh steel.