A medical worker wearing a full protective outfit tests a man for Covid-19 symptoms in a street in Wuhan, China, 01 April 2020. Wuhan, the epicenter of the coronavirus outbreak, partly lifted the lockdown allowing people to enter the city after more than two months. According to Chinese government figures over 2,500 people have died of Covid-19 in Wuhan since the outbreak began. (Photo by Roman Pilipey/EPA/EFE)

A grasshopper in a protective mask created by microminiaturist Anatoly Konenko in Omsk, Russia on May 21, 2020. Mini-masks about the size of a rice grain are made of a special high-density medical fabric with a built-in air filter. Anatoly Konenko is one of Russia's most famous microminiaturists; his works include a grasshopper playing a violin, a shod flea, a miniature bass guitar, a camel train in a needle's eye, and over 200 miniature books. (Photo by Yevgeny Sofiychuk/TASS)

A disinfection worker wearing protective gear sprays disinfectant to a medical worker after they perform swab tests for the coronavirus disease (COVID-19) during mass test at Islamic boarding school of Sunan Pandanaran on July 29, 2020 in Yogyakarta, Indonesia. Indonesia is struggling to contain hundreds of new daily cases of coronavirus amid easing of rules to allow economic activity to resume, has reported more than 100,000 coronavirus cases and with at least more 4,900 recorded fatalities. (Photo by Ulet Ifansasti/Getty Images)

Medical residents, who removed their clothes to protest against working conditions, take part on a protest during a strike in Barcelona, Spain, Tuesday, October 20, 2020. Regional authorities across Spain continue to tighten restrictions against a sharp resurgence of coronavirus infections that is bringing the country’s cumulative caseload close to one million infections, the highest tally in western Europe. (Photo by Emilio Morenatti/AP Photo)

Medical staff in Belgrade, Serbia on February 5, 2021. Vaccination of employees in the city's social protection institutions has begun at the Belgrade Fair, who have expressed interest in receiving the Russian Sputnik V vaccine, and according to the city secretary for social protection Natasa Stanisavljevic, about 150 employees in those institutions will receive the vaccine today and tomorrow. (Photo by Zoran Zestic/Tanjug)

Protesters wearing inflatable breasts stand outside Facebook's headquarters in central London on Wednesday September 1, 2021, to complain about the social media giant's images algorithm. The aim of the event is for all medical tattoo artists and breast cancer survivors to be able to freely post images without the pictures being removed and the accounts blocked. (Photo by Ian West/PA Images via Getty Images)

Coloured X-ray of a barn owl. A physicist has used X-ray to create an extraordinary collection of artwork. Arie van't Riets pictures reveal birds, fish, monkeys and flowers in an incredible new light. The 66-year-old, from Bathmen in the Netherlands, began X-raying flowers as a means to teach radiographers and physicians how the machine worked. But after adding a bit of colour to the pictures, the retired medical physicist realised the potential for an exciting new collection of art. (Photo by Arie van't Riet/Barcroft Media)

“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)