When the sea is ferocious, on the early part of the Piʻilani Trail and just north of Pa'iloa Beach you'll find this dramatic blowhole (it's signposted). Connected to a submerged cave, it violently spews water out of the precipice up to around 15ft during its mightiest roars – you'd best be standing back when it does. However, it's not an everyday event; keep an eye on local swell charts or surf reports if you're hoping to see it in action.
Blowhole
The Road to Hana