Top Ten Japan Classic Adventures

Picking up moisture from the Sea of Japan, freezing winds from Siberia dump enormous amounts of snow on Japan's western seaboard and central Gunma mountains during winter. The mountains—which receive as much snow as the northern island of Hokkaido—are piled with deep snow until spring arrives and the melted snow runs to fill the area's the rivers. What results is some of the most adrenaline-pumping whitewater rafting, past mountain peaks and steep ravines along Japan's Tonegawa River.

Bone-chilling rapids run from a merry Grade II to tear-jerking Grade V and are highest from May to July. You'll find reputable companies and launching sites in Minakami town. As the water warms during summer, swimming in the canyons between rapids can be a great way to relax and enjoy what's left of Japan's untouched ecosystem.