The Grand Line is a fictional sea route in the popular anime and manga series One Piece. It is known for its unpredictable weather, dangerous sea creatures, and powerful pirates. The Grand Line is divided into two halves by the Red Line, a massive continent that encircles the world. Sailing the Grand Line is a significant challenge for pirates, including the main character, Monkey D. Luffy, and his crew, the Straw Hat Pirates. Many seek the legendary treasure known as the One Piece, which is said to be located at the end of the Grand Line.