After a six hours flight, our plane makes a strong right turn. I look out of the little window and see a big crater below us, flying around our large-capacity aircraft. Finally, we arrive! We arrived by Honolulu, because this is Diamond Head, the famous landmark on Oahu island. Anyone who comes to the Hawaiian islands knows this 232 meter high and 1.5 square kilometer crater, which was created about 300,000 years ago. Oahu island is about 2.5 million years old and created by two large volcanoes, the Wai’anae and the Ko’olau which is connected by a wide saddle, at the origin. The two volcanoes grow the island from a length of 64 km and a width of 42 km. The highest point of the island is Mount Ka’ala of 1,200 meters and the longest river on the island is the Anahulu River. Due to the large eruptions of the fire-spitting Ko’olau volcano, the magma was processed by the sea water into ashes and dust, which in turn were thrown into the air by the strong winds and pressed together into so-called tufa rings and cemented. The wind direction can still be seen today at the Diamond Head, whereby the south-westernmost point could grow highest with the Tuffring.
The name „Diamond Head“ was given by western sailors and traders around 1700 AD. They believed that the stones glittered in the sunlight were diamonds. They had to accept a great disappointment when they discovered that it was only calcite crystals in the stones.
The earlier history of the crater by the Hawaiians, there are various legends.
The one Pele and Hi’iaka says that the sister Hi’iaka, sister of Pele, Fire Goddess Pele, gave the name Lē’ahi, because the summit resembles the forehead (lae) of the ‚ahi fish. Another translation gives the name of the crater as Fire Headland and goes back to when navigation beacons were lit on the summit. These bonfires were the help and safety of the canoes that sailed along the coast. Also, a heiau (or temple) was built at the summit. This temple was dedicated to the wind god Paka’a, who had to look for protection against updrafts, so that the fires on the crater rim can not be extinguished. Since 1917 there is a light to visually support nativators. In the 17th century, Western explorers and traders visited Lē’ahi and held calcite crystals in diamonds. The mountain became known as Diamond Head.
(Translated from the Diamond Head (Le’ahi) State Monument, Honolulu, Oahu, State Of Hawai’i Parks)
With its panoramic views from Koko Head to Wai’anae, Diamond Head is the ideal place for O’ahu’s coastal defense. In 1904, Diamond Head was bought by the government and served from that point on military purposes.
In 1908, the construction and installation of guns began, as well as the construction of the Kapahulu Tunnel through the north face of the crater to Fort Ruger. Five batteries were built to accommodate coastal artillery. Harlow (1910) on the northern crater rim, Dodge and Hulings (1913) on the east, Birkhimer (1916) in the crater mostly underground and battery 407 (1943), which is located in the southern crater rim. The fire station on the summit, built between 1908 and 1910, housed spaces for maps and instruments to coordinate the artillery strikes. From this position, the observers were able to assign targets to their own batteries as well as the Randolph and Dudley batteries at Fort DeRussy in Waikīkī and the Harlow battery at Fort Ruger. The four-storey fire station, the levels are interconnected by a spiral staircase and ladders, was masonry-clad with quarry stone embedded in cement. Each level has seaward slots to detect potential sea and air strikes. Additional coastal defense was provided by long-range cannons built on the slopes and crests of the 1915 crater. The Diamond Heads military features are part of the Fort Ruger Historic District.
In the 1940s, the Kāhala Tunnel was dug through the southern wall of the crater. This leads today to a parking lot within the crater from which a path leads over stairs and tunnels to the fire control station 232 meters in height.
The crater itself also had some military facilities, such as two shooting ranges.
In 1986, the Diamond Head was declared an important landmark (National Natural Landmark) of The United States.