Halona Blowhole, Blowhole rock formation at Hālona Point, Oahu, United States.

Halona Blowhole is a rock formation on Oahu's eastern coast where water shoots upward through a lava tube beneath the surface. The seawater gets forced up and sprays out dramatically when waves push through the underground passage.

The structure formed thousands of years ago when Koko Crater's volcanic activity created lava tubes that extended toward the ocean. Over time, ocean waves and erosion wore away the rock and exposed these underground channels to the surface.

In Hawaiian, hālona means "lookout", a name given to this point above the Pacific. Hālona Cove beside it is known locally as "Cockroach Cove", a small sand pit used for swimming when the surf is calm. In winter, visitors watch humpback whales and honu, the Hawaiian green sea turtle, from the point.

The blowhole is most active at high tide with strong winds, when spray can rise up to thirty feet. Parking sits along the Kalanianaole Highway at Hālona Point, and the viewing area is a short walk from the lot. Stay behind the barriers: the rocks are wet and slippery, and the Ka Iwi channel below carries one of the world's most dangerous currents.

Hālona Cove, nicknamed "Cockroach Cove", is the small sand pit beside the blowhole where the 1953 film From Here to Eternity shot its famous beach scene with Deborah Kerr and Burt Lancaster. The same cove later appeared in 50 First Dates with Drew Barrymore and Adam Sandler, and the blowhole itself features in Jurassic World: Fallen Kingdom.