The basalt columns at Takachi­ho Gorge were formed some 270,000 years ago as a result of four erup­tions of the Mount Aso vol­cano. Since, the Gokase Riv­er has cut through the columns, cre­at­ing a nar­row, V‑shaped chasm through which beau­ti­ful blue-green water flows. Boats float down the four-mile gorge in the shad­ow of these 300-foot, red-tin­t­ed cliffs. The site has been pro­tect­ed as a Nation­al Scenic Spot and Nat­ur­al Mon­u­ment in Japan since 1934.