The Ha?iku Stairs, also known as the Stairway to Heaven or Ha?iku Ladder, is a steep hiking trail on the island of O?ahu.
The trail began as a wooden ladder spiked to the cliff on the south side of the Ha?iku Valley. It was installed in 1942 to enable antenna cables to be strung from one side of the cliffs above Ha?iku Valley to the other. A building to provide a continuous communication link between Wahiawa and Ha?iku Valley Naval Radio Station was constructed at the peak of Pu?ukeahiakahoe, elevation about 2,800 feet (850 m). The antennae transmitted very low frequency radio signals from a 200,000-watt Alexanderson alternator in the center of Ha?iku valley. The signals could reach US Navy submarines as far away as Tokyo Bay while the submarines were submerged. Testers for RCA picked up signals on Long Island, and the signal also reached India, 6,600 miles (10,600 km) away.
