By Carolyn Conte | The Duquesne Duke In the newly completed Tower at PNC Plaza, one of the greenest office buildings in the world, employees flush the toilets with rain water. As people bustle around downtown Pittsburgh on a busy Monday afternoon, several stop in their tracks to look up at the 800,000 square foot, 33-story tower located on the southeast corner of Fifth Avenue … Continue reading Eco-friendly PNC tower opens Downtown