Mystical Scenery Carved by the Waves of Genkai Sea
Nanatsugama Caves are a national natural monument and a famous scenic spot. The caves are formed by the erosion of the rough waves of the Genkai Sea on the columnar joints of the basalt rock, creating a mystical sight with seven lined caves.
The most striking feature of Nanatsugama is its unique geological formations. The basalt rock forms regular columnar joints as the lava cools and contracts. These formations are then eroded by the waves, creating the seven caves. The largest cave has an entrance 3 meters wide and extends 110 meters deep, which is truly awe-inspiring.
These columnar joints, created as the basalt cools, form regular pillar-like fractures. The repeated wave erosion along these fractures results in the creation of the caves. Nanatsugama’s landscape is a perfect example of the combined forces of geological and marine processes, making it a natural masterpiece.
You can take a sightseeing boat to view the caves up close from the sea. Depending on the weather, you can see the intricate patterns of the columnar joints and the inside of the caves formed by the waves. The area above the caves is a grassy field with viewing platforms and walking trails, offering panoramic views of the entire Nanatsugama and the vast Genkai Sea.
Additionally, at the northern tip of the cape, there is a legend that Empress Jingu threw away earthenware vessels here to pray for victory in her expedition to Korea, and this site is now home to the Tsutsuzaki Shrine dedicated to her.
