I was used to seeing mostly smallish domestic flight planes up close and to me they seemed big but not imposing. Once I saw one of them parked next to 747, and boy was I blown away. The small plane's fuselage was sort of same size as the 747's engine; and 747 had four of those engines! That's when I realised how humongous 747 is. I still marvel at human agency; not only can they build structures as big as 747 it can also fly across continent, reliably and safely carry hundreds of passengers in total comfort.