Whether Woodstock would have happened without Sky River is, of course, anybody’s guess, but Sky River absolutely would not have happened without an even less-heralded event called the Piano Drop, a one-day Dadaist spectacle held on April 28, 1968, in a tiny town (its population was just 455) northeast of Seattle called Duvall. As the name of the event suggests, the Piano Drop featured a dropped piano (which organizers hoped would land on a specially prepared wood pile with a resounding crash), plus music by Country Joe and the Fish. Depending on whom you talk to, at least 3,000 and as many as 5,000 people showed up for this experiment in sonic mayhem.