Unchained Melody by Il Divo is in B at 99 beats per minute and runs 3:31 across 54 bars. It uses 16 chords — B, G#m, E, F#, F#7, D#m, B7, D, 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? Unchained Melody guitar melody tab.