Julia Wolfe *12’s 2009 alternative-folk album Steel Hammer was inspired by the ballad about folk-hero John Henry, who, according to legend, hammered a steel drill into rock faster than a steam-powered drill. To write the piece, Wolfe studied more than 200 versions of the song, including recordings by Johnny Cash and Bruce Springsteen. The result, according to The New York Times, is a “wild hybrid” that includes electric guitar, banjo, mountain dulcimer, jaw harp, humming, and chanting.