The curving green slopes of Diamond Head dominate the Honolulu skyline, a stunning backdrop that has become an iconic Hawaiian scene. Hike the 0.75-mile (1.1-kilometer) trail to the top, or simply enjoy a picnic at its base.Known by locals as Le’ahi (brow of the tuna), Diamond Head is an extinct volcanic crater, a “tuff cone.” The circular mountain formation was shaped around 150,000 years ago by a short, intense eruption. With its rim at 760 feet (228 meters) above sea level, it’s the perfect height to be both a relatively easy climb and an excellent lookout point. Enjoy exceptional views of the now overgrown crater, Oahu island and Honolulu’s coastline.Follow the handrails and the informative signs all the way to the top. A walk along an unpaved path and over lava leads to some tunnels and staircases and, finally, the observation platform. Cool off in the sea breeze and take in some of the best views in Hawaii, with Waikiki Beach and Kapiolani Park directly below you and the Pacific Ocean stretching to the horizon. Take pictures of the lighthouse, or, if you are there in winter, of the breaching humpback whales that often migrate past this point.The 475-acre (192-hectare) Diamond Head State Monument area at the mountain’s base has picnic tables and benches, where you can enjoy your packed lunch. Alternatively, try one of the many eateries along Monsarrat Avenue, just opposite the entrance. Visit on Saturday mornings for the local farmers’ market and buy fresh, local produce or tasty snacks.The Diamond Head trail starts just beyond the entrance to the Diamond Head State Monument, on the coast east of Waikiki. You can get to the park on foot, by bus or car, and it opens from early morning to late afternoon. There is only a small charge for entering. The climb is steep and over an unpaved path, so wear good walking shoes. Also bring water, a torch for the tunnels and sun protection. Allow 1–2 hours for the hike.