Explain how Vanity fair came to be and what is on display there?

Vanity is a town set up to delay pilgrims on their journey by appealing to their vanity. A year-long carnival, Vanity Fair, is erected to appeal to the tastes of travelers and persuade them to give up their pilgrimage. Christian and Faithful face imprisonment and death for speaking out against the practices of the town. When Christian's family arrives, however, they are allowed free travel because the men of the group kill a monster that had bothered the town. I think the place is special to the Devil or Beelzebub.