Comment by ben_w

> Now ask them to do the Australia / Los Angeles one.

> "lol no"

Given how many people dream of megastructures, I bet someone has this as an interview question, some variant of https://what-if.xkcd.com/160/ — I'd guess "a few trillion, tens of trillions of USD" for floating-bridges with anchors etc., but that's just my uninformed not-a-civil-engineer guess.