The time is the late 1960s. Detroit muscle cars roam the streets. Woodstock is just around the corner. Passenger air travel is growing at an unprecedented rate. To stay ahead of this growth curve, Boeing designed a new 747 jumbo jet that will carry more passengers than ever before. Roughly in the same timeframe, BAC & Sud Aviation (now BAE and Airbus respectively) were challenged to fly a plane full of passengers faster than the speed of sound from New York to Paris in just 3.5 hours. During these amazing times, engineers were tasked with the impossible.
Imagine being tasked to attach the aircraft wings to the fuselage of either of these incredible machines. Each aerostructure would have its own unique set of challenges, not least of which would be the tools available at that time for large-scale precision alignment. Assembly tasks like these are difficult even with the advanced technology available today. Now visualize the challenge as the only solutions you had available to accomplish this job were optical scopes and plumb-bobs.