For a country of less than ten million people, Sweden is a monster in the world of music. You can start with ABBA (the second most successful group of all time) and trace things through producer Max Martin (who has produced more #1 hits than anyone except George Martin—and he had the Beatles) to current artists like Tove Lo and Lykke Li and The Hives.
How did they do it? The answer begins in the 1940s when cultural conservatives and church leaders banded together to protect the country’s youth from the “dance-floor misery” of degenerate music coming from America. They set up a system of music schools—no tuition and with free use of instruments—to show the young how morally uplifting classical music could be. When things loosened up in the 60s, interest exploded with the result being a whole country of tightly-linked musicians. Once that was in place, it was only a matter of time.