Saltstraumen Norway

Saltstraumen has one of the strongest tidal currents in the world. Up to 400 million cubic metres of seawater forces its way through a 1.9 mile long and 150 m wide strait every six hours. Vortices known as whirlpools or maelstroms up to 10 m in diameter and 5 m in depth are formed when the current is at its strongest. At this point, its claimed that the tidal current can reach 25 mph in speed