I think the Seattle Tour has a bunch of factoids of which each guide chooses their own subset. First time I took the tour, they mentioned that a bunch of the material for raising the streets came from San Franscisco, which had quite a thirst of lumber (and would occasionally catch fire and burn down, boosting that demand).

Flat bottom boats hold a lot of bulky cargo, but they're a nightmare when empty. So on the return trips they ballasted them... with fill dirt.