Waikato River is the longest river in New Zealand, running some 425 kilometers from Lake Taupo to the Tasman Sea just south of Auckland. the river is fed from as several streams on the side of Mount Ruapehu and Mangatoetoenui glacier on the mountainside, which are referred to as the Tongariro River prior to feeding into Lake Taupo. at the northeast side of the lake, the wide, meandering river wends its way past the town before funneling into a narrow canyon some 15 meters across, which is carved out of sediment laid down during the Oruanui eruption some 26,500 years ago. that eruption completely changed the landscape of the North Island, coating most of the land with tephra up to 200 meters deep, creating Lake Taupo, and changing the course of what is now the Waikato River from flowing northwest (towards the Pacific) to flowing northeast (towards the Tasman Sea). since the river settled on its northeasterly course, the canyon and falls have grown deeper and more forceful; some 200,000 liters of water tumble over the falls per second. the canyon is some 10 meters deep and the drop over the falls isn’t very dramatic, but the force of the water causes it to shoot out from the end of the canyon to the awe of thousands of visitors (including us!) each year.