I'll add, there's some fascinating stuff towards the end, like this:

> Block went for a walk on top of the vaults [Kings College Chapel in Cambridge]. “In thickness-to-span ratio, they were proportionally as thin as an eggshell. They were so thin I could feel them vibrating. When I jumped, I felt them bounce. And yet they were still strong and standing. When you have an experience like this, and really feel how exceptionally thin this totally unreinforced structure is, it really motivates you. You realize: Damn, we have forgotten something. We have forgotten this knowledge.”