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The Pilgrim's Progress, an opera by Ralph Vaughan Williams, is based on John Bunyan's allegorical novel of the same name. The opera follows the journey of Christian, a man who leaves his home and family to seek salvation. Along the way, he encounters various challenges and temptations, but ultimately reaches the Celestial City. Vaughan Williams' opera is a powerful and moving work that explores themes of faith, hope, and redemption.