Grieg wrote it in 1875 for Ibsen’s Peer Gynt: Peer stumbles into the hall of the Troll King, and the trolls want to eat him. The whole piece is one short tune in B minor, played over and over, faster and louder each time, until the hall collapses.
Grieg didn’t think much of it. He wrote that it reeked of cowpats and Norwegian self-satisfaction. It is now probably the most famous thing he wrote, heard in cartoons and car ads.
Still, it’s a perfect machine: one idea, one long crescendo, and two and a half minutes. Ravel’s Boléro does the same thing in fifteen.