Giant whirlpools, often called maelstroms, do occur in nature, though they are rarely the ship-swallowing abysses depicted in fiction like Twenty Thousand Leagues Under the Sea. These powerful vortices are typically created by the meeting of conflicting tidal currents in narrow straits or near rugged coastlines. The most famous example is the Saltstraumen in Norway, which produces whirlpools up to 10 meters (33 feet) in diameter and 5 meters deep; it is considered the strongest tidal current in the world. Another legendary site is the Moskstraumen off the Lofoten Islands, which inspired writers like Edgar Allan Poe. In Scotland, the Corryvreckan whirlpool can produce standing waves and a roar audible for miles. While these maelstroms are extremely dangerous for small boats and swimmers—capable of pulling objects deep underwater—modern large vessels are generally not at risk of being "sucked down." They remain awe-inspiring displays of the ocean's raw power, driven by the complex interaction of topography and the moon's gravitational pull.