Icelandic horses play on a stud farm in Wehrheim Frankfurt, Germany, as the sun rises on Thursday, May 21, 2020. (Photo by Michael Probst/AP Photo)

A girl goes to school just before sunrise in Frankfurt, Germany, Wednesday, December 11, 2019. (Photo by Michael Probst/AP Photo)

A model attends a fashion show at the “German Fetish Ball” in Berlin, Germany on May 12, 2018. (Photo by Hannibal Hanschke/Reuters)

Iceland foals stand together at a stud farm in Wehrheim near Frankfurt, Germany, Friday, July 15, 2022. (Photo by Michael Probst/AP Photo)

Icelandic horses play on a meadow in Wehrheim near Frankfurt, Germany, as the sun rises on Tuesday, May 28, 2024. (Photo by Michael Probst/AP Photo)

Two storks sit in their nest as the sun rises in Wehrheim near Frankfurt, Germany, Thursday, August 29, 2024. (Photo by Michael Probst/AP Photo)

The moon rises on the behind the “Torchbearer” statue in Hannover, Germany, Wednesday, November 5, 2025. (Photo by Julian Stratenschulte/dpa via AP Photo)

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.