U.S. President Donald Trump gestures during his visit to a section of the U.S.-Mexico border wall in Otay Mesa, California, U.S. September 18, 2019. Trump threatened to do “dastardly things” to Iran in response to the drone attacks on the world’s largest oil plant in Saudi Arabia. The US President indicated he is wary of involving America in another war in the Middle East – but he did not rule out a military attack. (Photo by Tom Brenner/Reuters)

Ivanelis Jimenez, front, and Veronica Barreto pose for the camera wearing Puerto Rican flag dresses as they welcome passengers exiting Carnival's Mardi Gras cruise ship, docked in the bay of San Juan, Puerto Rico, Tuesday, August 3, 2021, marking the first time a cruise ship visits the U.S. territory since the COVID-19 pandemic began. (Photo by Carlos Giusti/AP Photo)

“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)

In this photo taken on July 19, 2014, a man looks at an excavation as an A.R.M.H., Association for the Recovery of Historical Memory, volunteer digs on the search for the body of Perfecto de Dios, in a hidden grave in Chaherrero, Spain. Across Spain, volunteer teams of archeologists, anthropologists and forensic scientists head out every year on expeditions to dig for suspected mass graves – a legacy of Spain's fascist past during the time of General Francisco Franco. (Photo by Daniel Ochoa de Olza/AP Photo)

In this December 19, 2014 photo, a man stands beside his 1957 Chevrolet Bel-Air car in Havana, Cuba. U.S. car sales have been banned in Cuba since 1959. Cubans have been have been forced to patch together Fords, Chevrolets and Chryslers that date back to before Fidel Castro's revolution which can make it appear like the country is stuck in a 1950s time warp. Since the Communist economic system isn't likely to change soon, many of those cars will have to stay on the road for years. (Photo by Desmond Boylan/AP Photo)

A photographer has discovered a spectacular way of keeping warm during winter – using fire to heat up icy locations. Sam Scholes uses long-exposures to capture the movement of fire in front of ice-covered backdrops. After lighting steel wool his friend Scott Stringham swings the flaming object in order to make swirling patterns. The result of this technique – captured at Midway Ice Castles in Utah is a vibrant image with the warm light dancing across the cold scenes. (Photo by Sam Scholes/Caters News)

A Kurdish female fighter from the People's Protection Units (YPG) gestures as she carries her weapon near al-Hawl area where fighting between Islamic State fighters and fighters from Democratic Forces of Syria are taking place in south-eastern city of Hasaka, Syria November 10, 2015. (Photo by Rodi Said/Reuters)

Men sleep at a 24-hour McDonald's restaurant in Hong Kong, China November 10, 2015. A large number of homeless people sleeping on the street has long been been a problem in Hong Kong mainly due to its high rent and soaring property. In recent years, McDonald's 24-hour fast food shops opening all over the city have become popular alternatives for people, know as McRefugees or McSleepers, to spend the night in a safer and more comfortable way than on the street. (Photo by Tyrone Siu/Reuters)