It is that Kauai is the largest canyon in the Pacific. The canyons are formed by a process of erosion, but that of Waimea has also been created by the collapse of a volcano that gave birth to Kauai (the oldest island of the archipelago of Hawaii). The Waimea River has subsequently caused an incision, the rest of the canyon has continued to be carved by rivers and floods from the summit of Mount Wai'ale'ale, there are several million years. (more...)