Materials had to be extracted and refined to exacting specifications, plans had to be developed and then edited, remade and edited again until they were nothing short of perfect.
A million things had to go right to make it possible: the plane had to be built by hundreds of skilled workers, drawing on the technical innovations of literal centuries to produce a colossal metal marvel that astounds casual observers even today. When you think about it it's really sort of a minor error, a plane crashing into the side of the mountain.
