Hālona Blowhole

Hālona Blowhole is a rock formation and a blowhole on the island of Oahu off of Hanauma Bay at Hālona Point. On windy days when the tide is high, the ocean breeze sends the waves rolling on to the shore where the rock formation then shoots sea spray high into the air through the cave acting like a geyser. It is not always at its best every day though. The blowhole is most active when the tide is high and the winds are strong.
-from Wikipedia