Coleridge took laudanum and fell asleep, dreaming of writing a poem about Kubla Khan building a palace. When he awoke, he wrote down 54 lines but was interrupted by a visitor before finishing. The poem uses imagery and supernatural elements to depict Kubla Khan's pleasure dome and the sacred river Alph, representing creativity and nature. It has an AABB rhyme scheme and explores themes of imagination, man's relationship with nature, and the interaction of creation and destruction.