They're aqueducts. Didn't Timekeeper teach you anything? And Trevor....While I agree that water bridges are cool, they are far from uncommon.
![Smile :) :)](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png)
The Barton Aquaduct on that list is ten minutes from where we live. It's very cool. And old. Watching it swing fully loaded with water is quite the sight.