In the 1970's a song by Tony Orlando and Dawn, became very popular called, 'Tie a Yellow Ribbon Round the Old Oak Tree'.
http://www.youtube.com/watch?v=H4cyCuj3H9I (Child safe video with lyrics.)
http://www.youtube.com/watch?v=wWn1Oj2V7Xw (Caution: You may die from laughing video.)
Within months, I began seeing yellow ribbons tied around trees, while driving. Over time, people began leaving flowers or flags, as a makers of an accident or special occasion. This song added an element to our American life.
The Question: Is there a song in your country which impacted your society like this...? (Please give a url.)
The Divine Comedy《忐忑》in chinese!