Haiku Stairs, Hawaii

Known as the Stairway to Heaven, this fairly unknown hiking trail can be found on the island of O’ahu. The trail is steep and ends at a peak 2,800 feet above the sea, which offers amazing views of the island.

The trail began as a wooden ladder spiked to the cliff on the south side of the Haʻikū Valley. It was installed in 1942 to enable antenna cables to be strung from one side of the cliffs above Haʻikū Valley to the other. A building to provide a continuous communication link between Wahiawā and Haʻikū Valley Naval Radio Station was constructed at the peak of Puʻukeahiakahoe, elevation about 2,800 feet. The antennas transmitted very low frequency radio signals from a 200,000-watt Alexanderson alternator in the center of Haʻikū 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  away.

When the Naval base was decommissioned in the 1950s, the United States Coast Guard used the site for an Omega Navigation System station. In the mid-1950s, the wooden stairs were replaced by sections of metal steps and ramps — by one count, 3,922 steps. The station and trail were closed to the public in 1987. Some hikers ignore the No Trespassing signs and continue to climb, contributing to the local community’s misgivings about reopening the structure.

Source : Wiki