I live in Pittsburgh. The air is clean now and the water is clear - but there's constant reminders that it wasn't always this way. Although most of the historic

I live in Pittsburgh. The air is clean now and the water is clear - but there's constant reminders that it wasn't always this way. Although most of the historic buildings were cleaned of soot, a few chose to keep some parts sooty and black as a reminder of what once was - a great example is the Mellon Institute just a few blocks from my work (https://www.atlasobscura.com/places/mellon-institute-columns https://www.atlasobscura.com/places/mellon-institute-columns). It did take Pittsburgh a long time to start fixing its environmental issues, and it took the total collapse of the steel industry to fully clear the air. Even back when I came here (~2011) people had an impression of Pittsburgh as a polluted, industrial hell-hole - I'm so glad that it wasn't the case when I came.