Hawaii sea arch collapses into Pacific Ocean after centuries

A famous natural arch in Hawaii fell into the ocean on Sunday, September 27, 2026. The Holei Sea Arch, located at Hawaii Volcanoes National Park on the Big Island, had stood for around 550 years. It was about 90 feet tall and stretched out from tall sea cliffs into the Pacific Ocean. The arch formed when ancient lava flows met the cliff edge and slowly carved a curved opening. Over centuries, softer rock wore away faster than harder rock, a process called differential erosion, and this eventually caused the collapse. Park staff knew the arch would fall one day because of constant wave action, but they could not predict when. Visitors had been warned to stay away from the unstable cliff edges.