Pittsburgh is located in the southwest of the state, at the confluence of the Allegheny River and the Monongahela River, forming the Ohio River. Pittsburgh is known both as "the Steel City" for its more than 300 steel-related businesses and as the "City of Bridges" for its 446 bridges. The city features 30 skyscrapers, two inclined railways, a pre-revolutionary fortification and the Point State Park at the confluence of the rivers. The city developed as a vital link of the Atlantic coast and Midwest, as the mineral-rich Allegheny Mountains led to the region being contested by the French and British empires, Virginians, Whiskey Rebels, and Civil War raiders.