Can you write a short summary of The Pilgrim's Progress?

The Pilgrim's Progress is an allegory
whose protagonist, Christian, appears to the author in a dream. The first part of the
book tells the story of Christian's journey from the City of Destruction, which he flees
thanks to Evangelist's warning, to the Celestial City. Christian travels with Faithful
and Hopeful. The second part tells the same journey made by Christian's wife,
Christiana, and their children following a vision. Christiana is accompanied by her maid
Mercy. The City of Destruction, the point of departure of both journeys, represents
wordliness and, to progress from this godless state to the Celestial City, Christian and
later his wife have to overcome the many obstacles in the Slough of Despond, the Valley
of the Shadow of Death, the Vanity Fair, the Doubting Castle and the Delectable
Mountains.