"The Long-expected Party" refers to the celebration of the birthday of Bilbo Baggins, a central character in J.R.R. Tolkien's novel, "The Hobbit." This event is significant as it marks both Bilbo's eleventy-first (111th) birthday and the unexpected departure from the Shire. The party is grand, featuring fireworks, food, and entertainment, showcasing Bilbo's wealth and status among the Hobbits. During the party, Bilbo surprises his guests with a magical disappearing act, leaving them in awe. He uses a special ring, the One Ring, to vanish, which sets the stage for his journey and the events that follow in "The Lord of the Rings." The party symbolizes the end of an era in the Shire.