Dance On A Volcano Lyrics

Lyric discussion by IonStar 

Cover art for Dance On A Volcano lyrics by Genesis

''Crosses are green and crosses are blue''

What exactly is the meaning of this line? I've been wondering about this for awhile now.

Maybe the cross in Puerto La Cruz, Venezuela, which, at night, glows between red, green and blue, but all 3 of those colours would have been too many syllables. I don't know if it was glowing in '76, though.