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 man uses a floating pitcher to catch a fish after removing it from a net at Keenjhar Lake, near Thatta, February 22, 2015. This technique of fishing using floating pitchers is a unique and traditional one for this community, found only on Keenjhar Lake, one of the largest freshwater lakes in Pakistan, which is famous for its variety of breeding and wintering waterbirds. (Photo by Akhtar Soomro/Reuters)

Boats moored in the middle of Dal lake are silhouetted against the setting sun on January 15, 2018 in Srinagar, the summer capital of Indian administered Kashmir, India. Kashmir, the Muslim majority state, known as the “Paradise on Earth” has for centuries captured the imagination of many writers, poets and film makers and is integral to the tourist trade. Kashmir has been a contested land between nuclear neighbors India and Pakistan since 1947, the year both the countries attained freedom from the British rule. (Photo by Yawar Nazir/Getty Images)

A Hindu devotee lies on a road as the holy “Rath”, or the chariot of lord Jagannath, passed over her during the Rath Yatra, or chariot procession in Karachi, Pakistan, July 17, 2016. Ratha-jatra is derived from two Odia words ratha/rotho meaning “chariot” and jatra meaning “journey”. The festival involves an annual procession (journey) of a deity's idols. Other names for the festival include ratha jatra or chariot festival. (Photo by Akhtar Soomro/Reuters)

A Pakistani feeds his goat wearing the words “Eid Mubarak” or “Eid Greeting”, to be slaughtered on the Muslim holiday of Eid al-Adha, or “Feast of Sacrifice”, in Islamabad, Pakistan on Tuesday, October 15, 2013. Muslims all over the world are celebrating Eid al-Adha by sacrificing sheep, goats, cows and camels, to commemorate the Prophet Abraham's readiness to sacrifice his son, Ismail, on God's command. (Photo by Anjum Naveed/AP Photo)

An Afghan teacher, in brown, helps school children run from the site of clashes near the Pakistan consulate in Jalalabad, capital of Nangarhar province, Afghanistan, Wednesday, January 13, 2016. Several members of the Afghan security forces were killed Wednesday after unidentified gunmen attacked the Pakistani consulate in a volatile eastern province, an official said on Wednesday. (Photo by Mohammad Anwar Danishyar/AP Photos)

“The Naval and Military Club is a gentlemen's club in London, England. It was founded in 1862 because the three then existing military clubs in London – the United Service, the Junior United Service and the Army and Navy – were all full. The membership was long restricted to military officers. This is no longer the case, but it still has a predominantly military and ex-military membership”. – Wikipedia

Photo: Members of the prestigious “In and Out Club”, one of the oldest and most exclusive clubs in London, march around St. James's Square during the club's 150th birthday celebration on March 1, 2012 in London, England. Patrons of the private members club, whose official title is the Naval and Military Club, gathered in St. James's Square in Central London before marching with the Band of the Royal Logistics Corps to be greeted by HRH The Duke of Edinburgh, and retiring for lunch inside the club. (Photo by Dan Kitwood/Getty Images)

“Igor Sikorsky (May 25, 1889 – October 26, 1972), born Igor Ivanovich Sikorsky was a Russian American pioneer of aviation in both helicopters and fixed-wing aircraft. He designed and flew the world's first multi-engine fixed-wing aircraft, the Russky Vityaz in 1913, and the first airliner, Ilya Muromets, in 1914. After immigrating to the United States in 1919, Sikorsky founded the Sikorsky Aircraft Corporation in 1923, and developed the first of Pan American Airways' ocean-conquering flying boats in the 1930s. In 1939 Sikorsky designed and flew the Vought-Sikorsky VS-300, the first viable American helicopter, which pioneered the rotor configuration used by most helicopters today. Sikorsky would modify the design into the Sikorsky R-4, which became the world's first mass-produced helicopter in 1942”. – Wikipedia

Photo: Westland Sikorsky H-5's, used by British European Airways Helicopters, which fly between London and Birmingham. The Sikorsky H-5, (aka R-5, S-51, HO3S-1, or Horse) (R-5 until 1948; company designation VS-327) is a helicopter built by Sikorsky Aircraft Corporation, formerly used by the United States Air Force, and its predecessor, the United States Army Air Forces, as well as the United States Navy and United States Coast Guard (with the designations HO2S and HO3S). (Photo by Harrison /Topical Press Agency/Getty Images). 22nd May 1951