Tupolev Tu-142MK, a Soviet and Russian maritime reconnaissance and anti-submarine warfare aircraft flies above a statue of Soviet Union founder Vladimir Lenin during a rehearsal of the Naval parade in St.Petersburg, Russia, Thursday, July 28, 2022. The celebration of Navy Day in Russia is traditionally marked on the last Sunday of July and will be celebrated on July 31 this year. (Photo by Dmitri Lovetsky/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.

In this handout photo provided by the U.S. Navy, the USS Stout launches a Tomahawk missile in support of Operation Odyssey Dawn March 19, 2011. This was one of approximately 110 cruise missiles fired from U.S. and British ships and submarines targetting about 20 radar and anti-aircraft sites along Libya's Mediterranean coast.

A sailor of the Marshal Shaposhnikov anti-submarine destroyer takes part in the “Vostok-2022” military exercises at the Peter the Great Gulf of the Sea of Japan outside the city of Vladivostok on September 5, 2022. The Vostok 2022 military exercises, involving several Kremlin-friendly countries including China, takes place from September 1-7 across several training grounds in Russia's Far East and in the waters off it. Over 50,000 soldiers and more than 5,000 units of military equipment, including 140 aircraft and 60 ships, are involved in the drills. (Photo by Kirill Kudryavtsev/AFP Photo)

China's Wang Yan performs on the balance beam during the artistic gymnastics women's individual all-around final at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Thursday, August 11, 2016. (Photo by Julio Cortez/AP Photo)

Air France airplane from Air France-KLM Group arrives at Princess Juliana international airport on the Caribbean island of Saint Martin at Maho Beach, Sint Maarten on February 12, 2023. (Photo by Rex Features/Shutterstock)

Alessandra Perilli, of San Marino, competes during the trap women's qualification at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Sunday, August 7, 2016. (Photo by Hassan Ammar/AP Photo)

Netherlands Antilles Sint Maarten – Boeing 747-400 of KLM in approach for the “Princess Juliana” airport on July 2, 2002. (Photo by LUPOO/Ullstein Bild via Getty Images)