During World War II, the US military built bunkers on top of Koko Crater with a railroad leading to its summit. In 1966, the air force ceded administration of Koko Crater over to the City of Honolulu. It was then renamed to the Koko Head Regional Park. Within this park is the Koko Crater Trail, which is a 1.8 mile long trail that uses the now-abandoned railroad as its pathway.