21 Guns by Green Day is in Eb at 84 beats per minute and runs 2:58 across 60 bars. It uses 24 chords — Gm, Eb, Bb, F, Am7, Dm, Dm7, C, and a few more. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? 21 Guns guitar melody tab.