A waterfall known for its thunderous roar. Selected as one of Japan’s 100 best waterfalls, Naena Falls has a drop of 55 meters as the Sekigawa River flows down from the mountains and marks the border between Niigata and Nagano Prefectures. It&srquo;s especially popular in spring when the melting snows greatly increase the flow of water, while all around are the new spring leaves. Autumn is another excellent time for the 15-minute hike back to the falls. Naena Falls is made up of basalt columns, known as columnar joints. Another feature along the trail are plate joints, where lava cooled to form what look like dozens of stacked boards.