“Dover Castle is a medieval castle in the town of the same name in the English county of Kent. It was founded in the 12th century and has been described as the “Key to England” due to its defensive significance throughout history. It is the largest castle in England.

The outbreak of the Second World War in 1939 saw the tunnels converted first into an air-raid shelter and then later into a military command centre and underground hospital. In May 1940, Admiral Sir Bertram Ramsey directed the evacuation of French and British soldiers from Dunkirk, code-named Operation Dynamo, from his headquarters in the cliff tunnels”. – Wikipedia

Photo: The Repeater Station in the subterranean tunnels underneath Dover Castle, which has been restored by English Heritage for a public exhibition on June 3, 2011 in Dover, England. The evacuation of allied soldiers from Dunkirk was masterminded and co-ordinated from the secret command and control centre in the tunnels deep below the castle. (Photo by Matthew Lloyd/Getty Images)

“The Space Launch System, or SLS, is a Shuttle-Derived heavy launch vehicle being designed by NASA, following the cancellation of the Constellation Program, to replace the Space Shuttle after its retirement. The NASA Authorization Act of 2010 envisions the transformation of the Ares I and Ares V vehicle designs into a single launch vehicle usable for both crew and cargo. It is to be upgraded over time with more powerful versions. The proposed SLS is visually similar to the legacy Saturn V booster and in particular the proposed, two-stage, Saturn INT-20”. – Wikipedia

Photo: In this illustration provided by NASA, the design for a new space rocket system, the Space Launch System, is seen. NASA's new rocket design will reportedly cost about $35 billion and be ready to for test launch in 2017. According to NASA, the rocket will be used to carry Orion Multi-Purpose Crew Vehicle as well as cargo and science experiments to earth's orbit, as a backup for the space station and possibly destinations beyond that. (Illustration by NASA via Getty Images)

“Space Exploration Technologies Corp. (SpaceX) is an American space transport company founded by PayPal co-founder Elon Musk. It has developed the Falcon 1 and Falcon 9 rockets, both of which are built with a goal of being reusable launch vehicles. SpaceX is also developing the Dragon spacecraft to be carried to orbit by Falcon 9 launch vehicles. SpaceX designs, tests and fabricates the majority of their components in-house, including the Merlin, Kestrel, and Draco rocket engines. In December 2010, SpaceX became the first private company to successfully launch, orbit and recover a spacecraft (a Dragon)”. – Wikipedia

Photo: Elon Musk, CEO of Space Exploration Technologies Corp, speaks during a news conference at the National Press Club April 5, 2011 in Washington, DC. Elon Musk, CEO of Space Exploration Technologies Corp (SpaceX) and Tesla Motors, held the news conference to announce SpaceX's Falcon Heavy rocket which could complete missions to the International Space Station and Moon and should be ready for use by the end of 2012. (Photo by Brendan Smialowski/Getty Images)

Russian support personnel work to help get Expedition 29 crew members out of the Soyuz TMA-02M spacecraft shortly after the capsule landed with Expedition 29 Commander Mike Fossum, and Flight Engineers Sergei Volkov and Satoshi Furukawa on November 22, 2011 outside of the town of Arkalyk, Kazakhstan. NASA Astronaut Fossum, Russian Cosmonaut Volkov and JAXA (Japan Aerospace Exploration Agency) Astronaut Furukawa are returning from more than five months onboard the International Space Station (ISS) where they served as members of the Expedition 28 and 29 crews. (Photo by Bill Ingalls/NASA via Getty Images)

A performer dressed as a Hello Kitty poses inside a Hello Kitty-themed Taroko Express train in Taipei, Taiwan March 21, 2016. Lucky fans of Hello Kitty were among the first to ride a train themed after the iconic fictional character on its inaugural run in Taiwan on Monday. The Hello Kitty-themed Taroko Express train, the first in Taiwan, set off from the Shulin train station and will travel to Taitung on the east coast route. The Taiwan Railway Administration, which will introduce Hello Kitty merchandise, said it plans to adds more themed trains to its fleet. (Photo by Tyrone Siu/Reuters)

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.

This handout picture released by the Gagarin Cosmonauts' Training Centre on October 17, 2023 shows Marina Vasilevskaya (L) flying during a parabolic flight aboard a zero-gravity simulator, a Russian IL-76 MDK aircraft used for cosmonauts' training flights in weightlessness, in Star City outside Moscow. (Photo by Pavel Shvets/Gagarin Cosmonaut Training Center/AFP Photo)

An employe of Russian Space Training Center hangs out to dry space suits of Russian cosmonaut Anatoly Ivanishin, NASA's U.S. flight engineer Kathleen Rubins, and Japanese space agency's flight engineer Takuya Onishi, right, after their undergoing training near in Noginsk, 60 km (38 miles) east of Moscow, Russia, Wednesday, July 2, 2014. The training was intended to simulate the capsule landing on water. Russian cosmonaut Anatoly Ivanishin, Japanese space agency's flight engineer Takuya Onishi, and NASA's U.S. flight engineer Kathleen Rubins are being trained for a future mission to the International Space Station. (Photo by Alexander Zemlianichenko/AP Photo)