John Lennon sang the song 'Imagine', it was recorded and released in the year 1971. 'Imagine' inspired the idea of world peace and influence younger kids to be anti-war protesters. The song related those times because it talked about world peace and at the time, we were fighting in the Vietnam War. John Lennon also sang Happy Xmas (War Is Over)”.
Imagine there's no countries it isn't hard to do - That means we all live on one land and in peace.
Nothing to kill or die for, and no religion, too - That means no war and no disagreements over people's belief systems.
Imagine all the people living life in peace... You... - That means there is zero war and zero disagreement.