"I'll be the first to admit it.. not sure if get it either??????"
I'm not sure either, but I'm guessing it's a shot from the evacuation of Saigon. Either that or an infusion of illegal aliens!
Yes, it's the retreat from Saigon. But this famous picture is not the US Embassy in Saigon. It's another pad used for the evacuation. Landed on top of the US Embassy on Christmas Day, 1969 as part of a contingency plan to protect the embassy in the event of another Tet.