To mark National Children's Day, Aled Jones visits Great Ormond Street Hospital in London to hear stories of faith and hope. In the Victorian splendour of the hospital's St Christopher's chapel, Aled meets the chaplain to find out how her role differs from chaplaincy in other hospitals, given the patients are all children. He also meets Caitlan, a 16-year-old heart transplant recipient whose road to recovery involved spending 262 days at the hospital.JB Gill joins a 22-mile walk from Kent to Great Ormond Street to raise awareness of a child who lost her life to a rare disease, and we find out about Mary Seacole, the Jamaican nurse who ended up on the front line of the Crimean War. Our hymn selection contains children's classics including Morning Has Broken and We Are Marching.