Dhaka, Oct. 3 -- Hawaii's famous Holei Sea Arch, a 90-foot-tall (27.4m) lava rock structure formed roughly 550 years ago, has collapsed into the Pacific Ocean, the BBC reports.

The precise timing of the collapse remains unknown, the report said, citing the National Park Service (NPS).

Whilst the formation was still projecting into the water from the coastline of Hawaii Volcanoes National Park on Sept 23, it had vanished by Sept 27.

"The coastline flanking the sea arch has shown signs of instability for years," the NPS said.

Park officials had previously warned in 2021 that the structure would ultimately crumble.

Located at the terminus of Chain of Craters Road on the island of Hawaii -- commonly referred to as "the Big Island" -- the...