The Sanctuary of Fátima annually welcomes hundred of thousands of pilgrims and tourists. Many come to participate in the celebrations that commemorate the apparitions of Our Lady to the three witness of Fátima. 

In the Fátima calendar, the dates May 13th (the first apparition) and October 13th mean a rise in the numbers visiting the Sanctuary – built on the site of the first apparition – and the places where the three children lived in Aljustrel, a village located around two kilometres away.

In Aljustrel, there is a religious route tracing the spots where Lúcia de Jesus, aged 10, and cousins Francisco and Jacinta Marto, aged nine and seven respectively, declared they saw the Angel of Our Lady of Fátima. 
Between April and October 1916, the three children bore witness that they saw the Angel on three occasions with them being invited to join in prayer and penitence.

In May 1917, the children were tending a small flock of sheep in Cova da Iria, within the parish of Fátima, in the council of Vila Nova de Ourém. Around mid-day, after saying the rosary as was their custom, they set about building a small construction out of loose stones on the spot where there now is the Basilica. 
Suddenly, they saw a brilliant light and above a small holm-oak tree (where the Chapel of the Apparitions now is) appeared a «Lady more brilliant than the Sun». The Lady told the three shepherds that much prayer was required and invited them to return to Cova da Iria at the same time on the 13th of each of the five following months. 
The children did just that and on the 13th of June, July, September and October, the Lady again appeared before them and talked to them. 
On 19th August, there was an apparition at Valinhos, some 500 metres from Aljustrel, as, on that 13th, the children had been taken by the Council Administrator to Vila Nova de Ourém.

For the final apparition, on 13th October, around 70,000 people were in attendance, the Lady told them she was the «Lady of the Rosary» and that they were to build a chapel there in Her honour. 
After the apparition, all those observed the miracle, promised to the three children in July and September: the sun, resembling a silver disc, could be looked upon without difficulty. It then began rotating, taking the form of a wheel of fire, seeming to disappear into the earth. 

Later, in Spain, Lúcia, who joined the order of Saint Dorothy, experienced a further three visions of Our Lady (10th December 1925, 15th February 1926 and during the night of 13th to 14th June 1929). 
The vision called for the five first Saturdays to be devoted to the conversion of Russia to the Immaculate Heart of Mary. 
This final request was part of the «Three Secrets of Fátima» – a set of revelations made to Lúcia by Our Lady. Lúcia later wrote to Pope Pius XIIth to inform him of what had been revealed to her. 

On 13th October 1930, the Bishop of Leiria gave the seal of church approval to the apparitions, officially authorising worship of Our Lady of Fátima, declaring it «Divine Providence».

13th May 2000, Pope John Paul II visited Fátima to beatify the witnesses Francisco and Jacinta Marto.