A whirlpool is a body of rotating water produced by opposing currents or a current running into an obstacle. They can occur in oceans, rivers, and lakes, often forming in narrow channels or near the mouths of rivers. The swirling motion can create a funnel shape, drawing in nearby water and objects. Whirlpools can vary in size and strength, with some being small and harmless, while others can be large and dangerous. Famous examples include the Maelstrom in Norway and the Narrows in the Strait of Messina. Understanding whirlpools is important for navigation and safety in water bodies.