Britain

This is, of course, a reference to the British invasion of music. Starting with the rise of the Beatles, the United States had a massive influx of British bands. These bands made the American bands work harder and reach greater heights in order to survive in the business. It is thanks to British music that American music has come so far.

List of British invasion bands: http://oldies.about.com/od/britishinvasion/British_Invasion_Bands_and_Artists.htm
British invasion encyclopedia article: http://www.britannica.com/EBchecked/topic/80244/British-Invasion