The Naruto Whirlpools, occurring in the Naruto Strait at the eastern end of the Seto Inland Sea, are among the largest whirlpools in the World.

The Seto Inland Sea, stretching out 450 kilometers from east to west between Honshu and Shikoku, leads to the Pacific Ocean at its eastern end, through the Naruto Strait which is only 1,3 kilometers wide.  As the water-level difference between the Seto Inland Sea and the Pacific Ocean is 1,5 meters, the massive water of these two seas periodically goes back and forth by a tidal force.  Thanks to the uneven seabed of the shallow strait, swift streams running at 20 meters an hour form many whirlpools here and there, whose diameters reach 20 meters maximum.  The Naruto Whirlpools were written in the history and literary books in the 8-10th century.  In the 17-19th century thereafter, many famous Ukiyo-e artists depicted them as a kind of guidebooks for travelers, which boosted the commoners in Edo into a distant sightseeing.  Nowadays, a variety of sightseeing boats are servicing for visitors.

In addition, the O-Naruto Bridge spanning over the whirlpools is equipped with a footway from where pedestrians can look down at them through glazed floor openings.

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