by Janie — The foun­da­tion of much of mod­ern civ­i­liza­tion? Sand, ac­tu­ally. It's a key in­gre­di­ent of con­crete, and to con­struct any build­ing you need a lot of it. It has to be sand from oceans, beaches, riverbeds, deltas, lakes. All that desert sand made slip­pery-smooth by wind ero­sion won't do...