BOSTON -- The voices of more than 400 children in song and prayer filled the Cathedral of the Holy Cross during a holy hour of adoration Oct. 6.

“We are the children of the world, answering Your call,” they sang. “You are the Savior of the world. Jesus in the Eucharist, I love You.”

The event, organized by the World Apostolate of Fatima in Boston, was the first of its kind held in the Archdiocese of Boston. Eleven Catholic schools as well as Catholic homeschoolers participated in the children’s eucharistic holy hour.

The World Apostolate of Fatima, a public association of the faithful under the pontifical council of the laity, has sponsored the World Day of Prayer in honor of Our Lady of the Rosary for four years. The annual worldwide event is intended to gather children of all faiths in prayer for peace and the families of the world. This year it will involve children from 110 countries in grades 2-8.

The local schools participating were: Cathedral Grammar School in Boston, Our Lady of Lourdes in Jamaica Plain, Our Lady of Perpetual Help Mission Grammar School in Roxbury Crossing, St. Anne in Readville, St. Bridget in Framingham, St. Catherine of Siena in Norwood, St. Francis of Assisi in Braintree, St. Joseph in Medford, St. Mary of the Hills in Milton, St. Mary Star of the Sea in Beverly and St. Paul in Wellesley.

Throughout the holy hour the American pilgrim statue of Our Lady of Fatima stood to the left of the cathedral’s main altar on which sat a monstrance containing the Blessed Sacrament. The Fatima statue made its first Boston appearance at the Respect Life Mass on Oct. 1 this year and will travel to over a dozen parishes throughout the archdiocese. The statue, gifted to the United States by Bishop Joao Venancio of Fatima in 1967, last came to Boston five years ago.

Becky Justin, treasurer of the apostolate in Boston, said the organization hoped to share the message of Fatima with the children and bring them closer to Jesus in the Eucharist.

The holy hour included adoration, songs and Scripture readings. The students were urged to pray for their own families and families all over the world. Throughout the service, the children took their cues from Cardinal Seán P. O’Malley and with him stood, sat and knelt.

Cardinal O’Malley addressed the children and said that Jesus gave His people many gifts before ascending into heaven. At the Last Supper He gave us the gift of the Eucharist, on the cross He gave us the gift of His mother Mary, and at the ascension He gave a promise of His continued presence on earth, he said.

Many people do not seek to thank God for His many gifts, he added.

“We live in a world that’s addicted to entertainment, and sometimes people come to church thinking that we go to church to be entertained,” he said.

Instead, Catholics must come to Mass to be with God and His people and to become people of prayer, the cardinal said. He urged the students to pray, learn the prayers of the rosary and seek to adore Jesus in the Eucharist.

“Today we come because our God loves us so much, He makes a gift of Himself to us in the Eucharist, He has given us His own mother and He has challenged us to accept the mission to spread His kingdom of love, truth, peace, service and goodness in our world,” he said.

After the cardinal’s words, students took turns praying the Hail Mary during a decade of the rosary. The children meditated on the annunciation, the first joyful mystery.

Father Edward M. Riley, parochial vicar of Immaculate Conception Parish in Weymouth and spiritual director for the World Apostolate of Fatima in Boston also spoke to the children. Jesus came into the world by asking Mary to be His mother, and she said “yes” at the annunciation, he told them.

“We ask that in your heart you ask the Lord what He wants you to say ‘yes’ to,” he added.

The service ended with the offering of petitions. Representatives from each school came forward to symbolically add the intentions of their community by placing a candle next to the altar.

Three students from Our Lady of Lourdes School in Jamaica Plain said their favorite part of the holy hour was the music. Michelle Grenier, 10, Rajive Alcindor, 11, and Irezzy Sanchez, 11, said they enjoyed singing “We are the Children of the World Answering Your Call,” a song they learned at school.

None of them had ever been to the cathedral nor met Cardinal O’Malley before. Irezzy said she liked the way the cardinal spoke and what he had to say. Rajive said the cathedral had a “good atmosphere.”

Michelle said she also enjoyed visiting the cathedral.

“I was thinking that this isn’t just a building,” she said. “It’s a church where you listen to God’s words and feel the peace of the Spirit in God’s sanctuary.”

Father Riley said it was great to have so many children come to the cathedral and pray for peace.

“There is nothing like gathering children in prayer,” said Father Riley. “That’s what’s going to change the world.”