National Gospel Day is observed in the Cook Islands every October 26, commemorating the arrival of Christianity to the islands by missionary John Williams in 1821. Williams, who volunteered with the London Missionary Society, initially landed on Aitutaki, where he began spreading Christianity, leading to the establishment of the first Christian church in 1823. The holiday is marked by singing religious songs and special masses held in churches across the islands. Additionally, both islanders and tourists enjoy spectacular fireworks and fire shows during the celebrations. National Gospel Day reflects the significant cultural and religious transformation that took place in the Cook Islands following the introduction of Christianity.