Today, I have been reading a lot about sewer systems on Wikipedia, in the hope that I would find information or at least photos showing what I think of as sewers, namely somewhere under the streets in a city where you can climb down through manholes with ladders and then walk around on little pavements down there, with rivers of sewer water flowing calmly around and the walls being made of rocks or something.
That's what I think of when I hear "sewer". But I found none of that.
I read about ancient sewers (with very few photos or illustrations of any kind) as well as saw a photo of some modern sewer pipe which definitely doesn't let you walk around in it. Nowhere could I see the "real" sewers, which I associate with Victorian-era England.
Basically, I wonder: why did they have to make them so large-scale? Why do humans need to go down there? And if they had to back in the day, then why don't they now, or in ancient times?
A ton of details are missing in my understanding of sewers. I've also always wondered how they could afford to do this everywhere in a large city. It seems like an insane amount of work just to transfer away some turds. Yes, I realize it's a crucial necessity to prevent diseases and provide for modern/convenient living, but still, it seems so wasteful (no pun intended) to build them so "roomy". Maybe that was only done for certain sections or something?
I especially wonder how in the world they were able to do this when the city was already made. Seems like you'd have to tear down all the houses if you want to make massive sewer systems, and then rebuild all the houses. Did they really do that?