Keaiwa Heiau State Recreation Area is the ruins of a temple (Heiau in the Hawaiian language) at the summit of a hill and neighborhood called Aiea Heights on Oahu, Hawaii. The recreation area includes camping facilities and a trail. It also offers clear views of Pearl Harbor. The high point of Puu Uau is about halfway down the trail, where native ohia lehua and koa trees may be viewed. The remains of a military plane that crashed in 1944 can also be seen along the trail. The hike is not particularly difficult, however it does include one quite steep switchback stretch and can be extremely muddy if it has just rained. Allow for around 2.5 hours of easy strolling. A possible translation of Keaʻiwa would be mysterious, incomprehensible. It is believed that this name was given in reference to the healing powers of the plants that no one could really explain. In addition, Keaiwa Heiau may have also been known as a "Heiau Hoʻola," or the healing or life-giving heiau according to native Hawaiian scholar Mary Kawena Pukui. Foresters replanted most of this area in the late 1920s. The lemon eucalyptus trees give forth a mild citrus scent in the air. The trail's lower end is marked by stands of Norfolk Island pine trees. Pu'u Uau, the trail's high point around halfway along the length, is surrounded by native koa and ohi'a trees. There is also wreckage of a B-24 aircraft that went down in 1944. The name "Keʻaiwa" means "strange" or "incomprehensible" un Hawaiian. Perhaps the name refers to the idea that the powers of the kahuna and the plants employed in healing are unfathomable. Erected sometime in the 16th century by Kakuhihewa, the 15th Aliʻi ʻAimoku, or ruling chief, of Oahu, the 100 feet (24 m) by stone temple had walls averaging 4 ft in height and 5 ft in width. The walls consisted of numerous evenly faced one foot stones that are filled with rubble. Abundant medicinal herbs in the area were used by kahuna as a type of ancient herbal clinic. The kahuna would also train haumana (students) interested in the art of laʻau lapaʻau (healing medicine). The kahuna would also train students in the practice of praying, fasting, and medicinal healing using the neighboring plants. The reputed healing powers of the surrounding plants still draws visitors who leave temple offerings, hoping to experience medicinal benefits.