Located in southwestern Pennsylvania in Allegheny County, Pittsburgh is the second largest city in the state. The city rose from where the Allegheny and Monongahela rivers unite at the point of the Golden Triangle to form the Ohio River. Much of the Golden Triangle has been redeveloped in the modern era and include projects such as the Civic Arena, Point State Park, and Gateway Center. Historically known for its steel manufacturing base, the Steel City now has a diversified economy based on healthcare, education, technology, and financial services. It is also home to such well known universities as Carnegie Mellon University, Duquesne University, and the University of Pittsburgh.