Nasty water

In the past 200 years or so the sanitation of water has increased greatly. The fact that there is filtration and processing for every drop of water that we drink is amazing. If you look at the sewer systems in chicago and new york and such, you can see all of the filth that has to be removed from the system for it to be clean. And i'm glad the sewers are underground and not on our streets and all over the place. The thing that fascinates me the most is that this was revolutionized in the mid 1800s which took lots of thinking and genius for back then.