The Haʻikū Stairs, also known as the Stairway to Heaven or Haʻikū Ladder, is a steep hiking trail on the island of Oʻahu. 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 (850 m). The antennae 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.

A view of the Hazelwood Power Station across the cooling pondage at sunrise on March 21, 2012 in Melbourne, Australia. The brown coal fueled power station, located in Latrobe Valley is the oldest in Victoria and provides the state nearly 25% of its energy. In 2005 Hazelwood was labeled Australia's least carbon efficient power station by WWF Australia and continues to be a target of issue of environmentalist groups. (Photo by Hamish Blair/Getty Images)

Twin baby panthers Remaong and Ferra cling to their basket while being presented to the media at Tierpark Berlin zoo on July 13, 2012 in Berlin, Germany. The two panthers were born in captivity on April 26. (Photo by Sean Gallup)

Actress Anne Hathaway attends the “The Dark Knight Rises” World Premiere at AMC Lincoln Square Theater on July 16, 2012 in New York City. (Photo by Jim Spellman)

Mercury and Maia, fueled and overhauled, are waiting in the Tay at Dundee, for favorable weather to start the flight to the Cape, a distance of 6,370 miles. The composite machine moored in the Tay River, at Dundee, on September 23, 1938. (Photo by AP Photo)

A woman moves a sandbag along a flooded road in the aftermath of the heaviest recorded rainfall in Zhengzhou in central China's Henan province on Saturday, July 24, 2021. Rescuers used bulldozers and rubber boats to move residents out of flooded neighborhoods in central China on Saturday after torrential rains killed at least 56 people. (Photo by Dake Kang/AP Photo)