Went on the Boeing Everett plant tour on Friday. Ventured inside the largest buidling in the world (you could fit Disneyland inside; over 1,000,000 light bulbs). It is where all the 747's, 777's, and 787's are produced. Saw the very first 747-800 passenger version being assembled.
I don't think there is another factory in the world where you could see billions and billions of dollars worth of work-in-process inventory just by turning your head. Very cool.