Century III Mall, Built on Steel Slag, Died With Pittsburgh Steel Century III Mall, Pittsburgh dead mall, steel slag mountain, West Mifflin history, Pittsburgh steel collapse, abandoned malls Pennsylvania, industrial decay PA #PennsylvaniaHistory #PANostalgia #Pittsburgh #DeadMalls #SteelTown The rise and fall of Century III Mall, once the third largest mall in the world, built directly on steel slag from Pittsburgh’s mills. A powerful metaphor for Pittsburgh’s industrial boom, collapse, abandon