What is the meaning behind this coin of Pope St. John Paul II?

I have in my possession a big coin in a nice box with the papal heraldry of Pope St. John Paul II. I am very curious Where this coin came from and why this coin exists. I have found many different pictures but none like the one I have. This is the entire object photographed. It seems my Grandfather and his brother who was a man of the cloth himself have been to Rome and may have gotten it in Vatican City. I found a photobook with pictures of him on St. Peter's Square and pictures of the Pope he made. (I cannot say which pope or time)