I can't think of any good non-american bands.
All they have to show for is Led Zeppelin and the Beatles, and they suck.
Oh my, the good 'ol US could stop all its middle-east shenanigans, and the world would still hate it for the likes of poster boys like this
Far be it from me to prove things otherwise to you - against such mind-boggling naivity I quail and prefer easier tasks such as solving quantum gravity...
But, thankfully for you, there really is no accounting for taste, and God may just overlook this on account of your age.
However, amzing to see just how many prog-rock followers there are on this board - personal all-time favourites:
Rush - Canadian
Yes - UK
Genesis - UK
Sigur Ros - Icelandic
Pink Floyd - UK