The bottom-most bridge was built around the 12th century. How the hell they managed to build stuff like this way back then staggers me.

I find it hard to relate with this sentence. That's just 3 bridges on the top of what seems like a natural rock formation, right? With 2 being arches and the top one being a modern-ish structure.

No matter how deep it is, it's narrow enough to just move a prebuild wooden foot bridge used for people to go around constructing the thing.