Kaimana Beach standing below Diamond Head
on the island of Oahu in Hawaii
Diamond Head is the name of a volcanic tuff cone on the Hawaiian island of O'ahu
and known to Hawaiians as Lēʻahi, most likely from lae 'browridge, promontory' plus ʻahi 'tuna' because the shape of the ridgeline resembles the shape of a tuna's dorsal fin.
Its English name was given by British sailors in the 19th century, who mistook calcite crystals embedded in the rock for diamonds.
It is the start of the Waikiki Roughwater Swim and the Hawaiian Christmas Looong Distance Invitational Rough-H2O Swim.