Allowing for the other usual things already mentioned;
The Les Paul electric guitar without which there would have been *no* Brtiish Pop invasion. ;-)
Yeah, right, the Beatles and the Stones could've made it as accoustic acts ;-)
For that matter I've often argued that Jimi Hendrix would *never* had made the sensastion he made had he not *first* gone to London , soaked up the culture of competitive guitar virtuosity of the time,and joined up with 2 equally talented Brit craftsman of drum and bass.
And the British virtuoso I always refer to as the Hendrix of the Keyboard, Keith Emerson had gone as far as he could've gone with the Hammond Bs organ until the american Robert Moog made the synthesizer.
And where would any of them be without Edison's phonograph?
And whilst waxing gadgety ,although I love the unique quality of the better Brit cinema ( "Man for All Seasons' one of my Top 5 all time favorites )
if there is nothing else uniquely American it's "da Movies"
(also thanks to Thomas Edison's motion picture camera ) and their various master craftsman directors/filmmakers. ( Orson Wells/John Huston , Disney, the makers of the "Wizard of Oz" etc, etc. )
One forgets that Jazz also means Gerschwin and Copeland.
Yeah ,our market is precisely "what we've ever done" for you by way of your economy. We've given plenty of other countries a lot of their GNP by them selling into our Amercian consumer culture ; good , bad and evrytthing in-between.
Ever wonder why the Beatles were knighted? Had something to do with that old joke about what the letters of the old British airlines B.O.A.C. stood for ( Bring Over Amercian Cash ) So what you Brits lost in tea you have more than made up for breaking into our markets with just da Beatles and da Stones.
So , you're all welcome ;-)