Complex sentence: While testing the previously the uncharted realms and possibilities of what the new world had to offer, 60s youth had ultimately to accept the accompanying limitations of living in a more advanced civilization in a period that was for many a "crash course" in history.
Split into simpler sentences: While testing the hitherto unexplored realms and possibilities of what the new world had to offer, 60s youth had ultimately to accept the accompanying limitations of living in a more advanced civilization. In certain ways the period was for many a "crash course" in history.