"It began to rotate and change colours so we saw all the colours of the rainbow. It lasted ten to fifteen minutes."
|May 13th 1917|
The spectacle apparently began during prayers in thanksgiving for the Beatification of Bl Pope John Paul II (who believed that it was the hand of Our Lady of Fatima that deflected the assassins' bullet).
However, whilst I know that my priest friend is totally reliable I cannot find any credible reference to this happening on the internet.