ANSWER
The Third Secret of Fatima is a prediction of the assassination of the Pope.
In 1917, three young shepherd children experienced visions of the Virgin Mary in a field near the village of Fatima, Portugal. The apparition of Mary appeared to them six times, always on the 13th of the month, for six consecutive months, the first appearance occurring on May 13th, 1917. Because the people of Fatima were greatly divided on the authenticity of these visions, the children asked Mary for a miracle to convince them.
On her sixth and final visit (October 13th) 70,000 people had gathered in the field, waiting for the miracle. Shortly after noon on the, the clouds parted, and according to witnesses, the sun came loose from the sky and danced around, spinning and whirling about in a brilliant display of color and light, and generally frightening the hell out everyone present.
During the six visitations, Mary revealed several predictions to the children, including the impending death of two of the children, Jacinta and Francisco Marto, who both died of the flu a few years later. The third child, Lucia dos Santos, who went on to became a nun, revealed two of the three secrets in 1941. These first two secrets seemed to predict the end of the World War, the beginning of a second, even larger World War, and the subsequent rise and fall of Soviet Russia as a world power.
When Sister Lucia became deathly ill in 1944 she was urged to write down the third secret, lest it be lost for all time. She complied, writing the secret in a letter and sealing it in an envelope with instructions that it was to be opened and read to the world by the Pope in 1960. The letter was forwarded to the Vatican, where it stayed unopened in the Vatican archives until 1960.
Pope John XXIII opened the letter in 1960, and after having read it to himself, returned it to its envelope, saying only that "this is not for our time". Every Pope since has read the letter, and made the same decision, declining to share its contents with anyone beyond a few high ranking officials within the Vatican.
On May 13th, 1981 (the same date as the first appearance of Mary in Fatima), Pope John Paul II was travelling through St. Peter's Square in his pope-mobile. Out of the corner of his eye he saw a young woman in white wearing a small picture of the Virgin Mary. As he turned bent down towards the young woman, two bullets, fired from close range, whizzed past his head. A third bullet struck him in the abdomen, nearly killing him. Had that image of Mary not caught his eye, he most likely would have been killed instantly by two shots to the head. The Pope has since credited Mary with saving his life that day.
The would-be assassin was a Turkish gunman named Mehmet Ali Agca. He testified at his trial that his attempt to kill the Pope was linked to the Third Secret of Fatima, and urged the Pope to reveal the "mystery of Fatima". No one took him seriously, since he also claimed at times to be Jesus Christ. The secret would remain a secret for several more years.
On May 13th, 2000, the Pope finally revealed the Third Secret to the public, in a ceremony to beatify two of the children of Fatima. (Sister Lucia is still alive today, and as such is ineligible for beatification.) The Third Secret predicted, among other things, the apparent assassination of the Pope by gunfire.
WHO GOT IT RIGHT: Stephen Finley.
