Located at strategic point, at the confluence of Allegheny & Monongahela rivers, forming the Ohio river. It is in an area of valuable natural resources; it was contested by French, British, and Native Americans in the 17th cen. The city of Pittsburgh was laid out in1764 by John Campbell in the area around the fort (now the Golden Triangle). Following the American Revolution, the town became an outfitting point for settlers traveling westward down the Ohio River. It developed as a steel manufacturing center in the 19th century; there has been urban renewal since World War II.