What do the lyrics mean/refer to?

Me no gets it

             D         G             A7         D
  I'm gonna walk that road that we walked long before, 
   Bm         D              A7
  many years ago, and we'll walk a hundred more.
  
             D            F#m              Bm    A7      D
  And we're comin' one by one. You didn't see us two by two. 
    D             Bm             A7
  Ev'ry time you turn around another's comin' through.
             D                F#m     G   A7       D  Bm 
  So we'll sing it long and proud so ev'ryone will know 
            D         G          E    A7           D
  That the road to freedom is a long, long way to go.
  
  
  Turn and look out over there, just as far as you can see. 
  There are many more who have died for liberty.