She exhorted the children to do penance and sacrifices to save sinners. They wore tight cords around their waists to cause pain, abstained from drinking water on hot days, and other works of penance.
On her last visit, a crowd of 70,000 people (including, the story goes, members of the sceptical, anti-religious press) witnessed the great Miracle of Fatima: some people in the crowd said that the sun began dancing around in the sky and went completely dark for several minutes before returning to its proper place, although there is no independent verification of this incident and no movement of the sun was registered by scientists at the time.
Most of the interest in Fatima, however, revolves around the famous three part secret of Fatima, which include remarkable visions of the future. The first described a horrific vision of Hell, while the second foretold the end of World War I and the beginning of World War II and called for the "Consecration of Russia to the Sacred Heart" Many believe Pope John Paul II fulfilled this request by giving a blessing over Russia shortly before the collapse of the Soviet Union, although many believed this blessing was not enough.
The third secret was kept under wraps by the Vatican until Easter 2000 -- despite the Virgin's declaration that it could be released to the public after 1940 and must be relased by 1960. When this did not happen, this led to immense speculation over the content of the secret. In short, people assumed that if the Popes chose to oppose the popular will and supposed will of Mary, it was because the content of the secret would be far worse to be revealed then not be revealed. The secret is described as foretelling the 1981 assassination attempt against the Pope, who was wounded when a Turkish gunman opened fire in St. Peter's Square. The shooting occurred on May 13, the date of the first of the reported Fatima visions.
There is some controversy that the third part of the secret revealed in the year 2000 was not the real secret. The most basic argument for this revolves around the decision to delay the release of the secret, against the known due date. It was thought that the secret might contain condemnatory remarks about the current pope (who obviously wouldn't want to release it), or that it might contrain inflamatory remarks about Russia (which would not be good to release during the cold war). Instead, the third part of the secret as revealed was by far the most unspecific, ambiguous, and uncontroversial part. Other reasons people doubt the authenticity include previous remarks that were made about the secret by those who knew about it or had read it. Some had said that the secret contained scripture almost totally, while Sr. Lucy said that its meaning as a whole was "Portugual would not lose the faith".
Of the three children, siblings Francisco and Jacinta Martos and their cousin Lucia dos Santos, only Lucia is still alive. She lives in the convent of the Carmelite Sisters of Coimbra, which she first entered in 1928. Francisco and Jacinta Martos both perished in the Great Spanish Flu Epidemic of 1919, and were declared "venerable" (two steps away from sainthood) in 1989. On May 13, 2000, both were declared blessed. (See Canonization for more on that process.)
Fatima is not without controversy. Many non-Christians, and some Christians, do not accept the Church's claim of veracity of the visions. In addition, the cult of the Lady of Fatima was used by the authoritarian Salazar regime to bolster itself in power and persecute liberal opposition. During the Salazar period it became almost obligatory to believe in Fatima. This long period of dictatorship was even referred by the opposition as the time of Fado, Fatima, and Football.