What's Fatima's Secret? Pope Francis to Visit famous Portuguese Shrine

Pilgrims walk on their knees to fulfil their vows at the Catholic shrine of Fatima in May 2017. Rafael Marchante/Reuters

A century ago, as the U.S. joined World War One and Russia was in revolutionary turmoil, a small town in Portugal entered the annals of history.

Three children claimed the Virgin Mary appeared to them in a field near Fatima as their sheep were grazing. Nine-year-old Francisco Marto, his seven-year-old sister Jacinta and their 10-year-old cousin Lucia dos Santos reported first seeing the Madonna on May 13, 1917, and five other times over the course of that year, as Lucia noted in a written account.

100 years since the first apparition, it is time for Pope Francis to make the pilgrimage - the fourth pontiff to do so - on Friday and Saturday.

"With Mary, as a pilgrim of hope and peace I travel to Fatima tomorrow. Let us see in her that everything is God's gift and He is our strength. I ask everyone to join me as pilgrims of hope and peace: may your hands in prayer continue to support mine," read a statement on Pope Francis's Twitter account.

Thousands of people from all over the world have begun congregating in Fatima ahead of the historic visit, marking the canonization of the two siblings. Francisco died in 1919 and Jacinta in 1920, and are expected to become the Catholic Church's youngest-ever non-martyred saints. Their cousin Lucia instead became a nun in the seclusive Carmelite order, and died in 2005 aged 97. Her beatification process began in 2008.

Besides demonstrating a holiness in life and heroic virtues, to qualify for the canonization process the children had to have at least one verified miracle attached to their name. On Thursday, parents of a Brazilian boy who claimed he was cured of a brain injury in 2013, spoke to the press about the supposed miraculous recovery, but did not allow any questions from the journalists, the Brazilian newspaper O Globo reported.

Fatima's children
Three young shepherds, Jacinta Marto (L), Francisco Marto (C) and Lucia dos Santos. Pope Francis will begin the canonization of Jacinta and Francisco in May 2017. Reuters

When the Fatima children first spoke of the apparition a century ago, they were not believed. In August 1917, they were jailed for three days in separate cells and threatened with being boiled alive in olive oil to get them to admit they were lying, as the Associated Press reported. Yet, the young shepherds were steadfast in their convictions and eventually the Catholic Church too accepted the apparitions as authentic in 1930.

The final apparition of the Madonna was recorded on October 13, 1917. The so-called "Miracle of the Sun" offered believers final proof that the apparitions were authentic, as others in Fatima reported seeing the sun spinning in the sky at the time of the apparition. Word of the visions spread across the country and beyond. Fatima increasingly became a pilgrimage destination ; nowadays, it welcomes around 6 million pilgrims a year.

Pope Francis Visits Fatima
A woman waits for the arrival of Pope Francis in Fatima, central Portugal, on May 12, 2017. The shrine is visited by millions of people every year. Patricia De Melo Moreira/AFP/Getty Images

According to the children, the Madonna shared with them three secrets, prophecies about the future of humanity. The first two secrets were revealed in 1942, but the world had to wait until 2000 to discover the third secret, after Lucia sealed its content in an envelope handed to the Vatican in 1957, captivating the imagination of believers all over the world and giving rise to endless conspiracies and apocalyptic writings.

Sister Lucia dos Santos kisses the hand of Pope John Paul II at the holy shrine of Fatima. The third secret is interpreted as having predicted the Pope's failed assassination attempt in 1981. Reuters

In the first of the secrets, now reported on the Vatican's website, the Virgin Mary described a vision of hell, a terrifying "great sea of fire," demons and human souls. The second is interpreted as the Virgin Mary's prophecy of the end of the First World War only for a new war to begin and, in particular, mentioning Russia spreading "her errors throughout the world, causing wars and persecutions of the Church" in an apparent prophecy of Soviet rule. The final prophecy, describing a scene of violence as the Pope and clergy climbed a mountain is interpreted as a the prophecy over the failed assassination attempt of Pope John Paul II, who was shot in 1981.