A few dozen people attend midday Mass. A handful of others light candles. A woman makes her way down a long, narrow path on her knees.

The expansive esplanade bounded by two massive churches is practically empty on the overcast March day when I visited. But on May 13, Pope Benedict XVI celebrated an open-air Mass here -- one is said the 13th of every month -- drawing hundreds of thousands to this sprawling shrine outside the town of 8,000, about 80 miles northeast of Lisbon.

Why here? Why now?

Because this sanctuary is where, on May 13, 1917 -- with Europe embroiled in World War I -- children reported seeing the first of six apparitions of the "Lady of the Rosary," urging them to spread her message of prayer and peace.

Lucia Santos, 10, and her cousins, Francisco, 9, and Jacinta Marto, 7, said they had received three messages, or secrets: a vision of hell, avoided through devotion to Mary; a promise that the war would end but would be followed by another war if Russia rejected God; and a third one, which could not be revealed before 1960.

In the final apparition, on Oct. 13, 1917, the children -- joined by a crowd of about 70,000 -- also were told that a chapel should be built in Mary's honor.

Today, the Chapel of Apparitions is the heart of the shrine, with a marble pillar and Statue of Our Lady marking the spot where she appeared.

The chapel is more modern than I expect, with full-length windows along the sides and back, the front open to the plaza, and a skylight covered with billowy gray fabric that looks like clouds. Some visitors sit on the simple backless benches for Mass; others stand or kneel.

Off to one side of the chapel are banks of candleholders (melted wax flows into a vat to be recycled); on the other side stands the holm oak tree that sheltered the children while they awaited the apparitions and prayed the rosary. In the center of the esplanade, a fountain provides water that pilgrims take home.

We make our way to the impressive neoclassical Basilica, flanked by porticos for the 14 Stations of the Cross and topped with a 200-foot spire. The aura is the same around the plaza and inside the church -- reverence and wonder. Everyone speaks in hushed tones. Entering, I'm reminded to remove my hat, and we're surprised that flash photography is allowed, except during Mass.

The Basilica's 15 altars are dedicated to the 15 mysteries of the rosary, but we linger longest at the tombs of the three shepherd children.

Francisco and Jacinta died within 2 1/2 years of the sixth apparition, victims of an influenza epidemic. Lucia, however, became a Carmelite nun and lived to age 97, returning for each papal pilgrimage -- Pope Paul VI's visit in 1967 for the 50th anniversary of the first apparition, and Pope John Paul II's three visits.

John Paul's first visit, on May 12-13, 1982, was in thanksgiving for his survival after being shot in Rome exactly one year earlier -- yes, on May 13.

"I owe it to Our Lady of Fatima to be alive today," the pope said after his recovery. And the bullet was later encrusted in the crown of the Statue of Our Lady in the Chapel of Apparitions.

The second visit came on the 10th anniversary of the shooting, and the third, in 2000, was for the beatification of Francisco and Jacinta. During that visit, the third secret of Fatima was finally revealed: The pope would be assassinated.

John Paul also ordered construction of the Church of the Holy Trinity in 2005, shortly before his death. The church, at the south end of the plaza, is as modern as the Basilica is ornate, with seating for 9,000 worshippers -- 10 times more than the older church. Yet the art behind the main altar in each church depicts Mary with the three seer children.

Curious about the children, we head for the rural hamlet of Aljustrel, about a mile away, where they were born and raised. Halfway there, we walk in their footsteps along what is now the Holy Way -- 14 Stations of the Cross and a chapel commemorating the Resurrection.

Their family homes are similar -- white stucco, one-story buildings with wood floors, a few bedrooms, and a cooking area, built in 1885 to 1888 and restored from 1987 to 2000. Lucia was the youngest of six children, Francisco and Jacinta the youngest of nine.

As we retrace our steps past the shrine to the bus station, we admire the courage and fortitude of these humble shepherd children, who persevered through intense interrogation and pressure about their visions to demonstrate the power of prayer.

They never could have imagined that their pasture would be transformed into a sanctuary that draws 4 million pilgrims a year.


If you go:

It was easy getting to Fatima from Lisbon.

The bus ticket costs about $10.40 each way, depending on the time of day. We paid one-way fares for flexibility, since all tickets are for a specific time.

Admission is free.