It's a good thing in this case that Inigo has so much mission experience at this point. After all, huge modern cities would be completely impossible for a medieval boy like him to imagine, were it not for the fact that he's seen a few in other worlds at this point. The city on Diagad, where they thought they had always lived. And huge, sprawling Kamakan..

It renders Inigo able to imagine the city Senku is talking about right now.

The city he's remembering, even though it's long gone at this point in this world, even way before Senku ever ended up on the train.

At first he says nothing, just allowing the other to let those memories flood back, but then he slowly speaks up.

"Did you want to rebuild all that? ... Make it go back to the way it's supposed to be?"