Even the darkest clouds can have a silver lining. From the Napoleonic Wars to the COVID-19 pandemic, read on as we look back over history's most trying times to reveal 32 revolutionary inventions and discoveries that were sparked by grave international emergencies.
All dollar amounts in US dollars.
The second plague pandemic began in 1346 with the Black Death, which claimed 200 million lives in Eurasia and Africa. Surviving members of the lower classes became better off as a result, and an unprecedented number of people were able to afford books.
The outbreak also massively reduced the population of monks who could transcribe manuscripts by hand, resulting in a surplus of rags (making paper cheaper) and leading to the creation of oil-based inks. These factors fuelled the development of the printing press, which was invented around 1440.
The second plague pandemic recurred regularly until the 19th century. One of the most infamous outbreaks struck London in 1665, wiping out almost a quarter of the city's population.
The pestilence prompted scientific pioneer Isaac Newton to self-isolate at his estate in Lincolnshire, where he came up with his groundbreaking theory of gravity while, as legend has it, sitting under an apple tree.
The Napoleonic Wars engulfed dozens of countries, and a slew of innovations came about as a consequence of the hostilities, which raged from 1793 to 1815.
These include the world's first ambulances. The horse-drawn vehicles were the brainchild of leading French surgeon Baron Dominique Jean Larrey, who also introduced triage and the mobile army surgical hospital (MASH).
Along with ambulances and other battlefield medicine innovations, the Napoleonic Wars led to the invention of the canning process. In 1810, the French government, which was seeking a way to preserve rations in order to feed its troops all year round, awarded confectioner Nicolas Appert a prize of 12,000 francs for his airtight food preservation process.
Appert duly invested his winnings, creating the world's first commercial cannery.
The third cholera pandemic hit London's Soho neighbourhood in 1854, killing 616 people. Physician John Snow (pictured) investigated the outbreak in depth and worked out its cause: contaminated water from a pump situated in Broad Street (now Broadwick Street).
Snow's findings proved once and for all that the disease lived in water rather than being airborne, and his research provided the foundation for modern epidemiology.
During the aptly named Long Depression, which lasted from 1873 to 1896, a hard-up Thomas Edison turned to his father for financial assistance and used the cash to set up his lab and machine shop in Menlo Park, New Jersey.
That's where he invented the world's first commercially successful light bulb.
The Long Depression also saw the invention of the modern steam turbine, which made affordable and plentiful electricity possible.
The revolutionary contraption was designed and patented in 1884 by Anglo-Irish engineer Charles Algernon Parsons, who was working for Clarke, Chapman and Company, a ship engine manufacturing firm based in Gateshead, northern England.
The flurry of Long Depression innovation continued into the late 1880s and first half of the 1890s. Having developed methyl ether-run fridges and later ones using ammonia, German scientist and engineer Carl von Linde managed to perfect the liquefaction of air in 1895 by compressing and rapidly expanding it, thereby cooling the constituent gases.
He went on to patent the process, paving the way for modern refrigeration.
World War I sparked several remarkable innovations. Although the zip fastener was first conceived during the 19th century, the technology wasn't fine-tuned or widely adopted until the global conflict, when it was used for flight jackets and money belts worn by US sailors who lacked pockets in their uniforms.
Synthetic rubber, which boasts a myriad of industrial applications, was first synthesised during the 19th century but wasn't manufactured on a meaningful scale until World War I when Germany, which was experiencing a shortage of natural rubber due to an Allied blockade, began mass-producing the multitasking material.
Towards the end of the World War I, the discovery of blood types and improved refrigeration methods enabled the long-term storage of blood and brought transfusions to the masses, something that wasn't possible before the conflict.
In fact, US Army doctor Captain Oswald Hope Robertson set up the world's first blood bank in 1917 on the Western Front.
While the drone appears to be a recent invention, the first unmanned aerial vehicles (UAVs) were actually developed during the First World War.
Early examples include the remote-controlled Hewitt-Sperry Automatic Airplane and the Kettering Bug (pictured), which was designed by aviation pioneer Orville Wright together with engineer Charles F Kettering.
Hailed as one of the most significant innovations of the 20th century, the process of transforming nitrogen in the air into ammonia fertiliser was developed by German chemists Fritz Haber and Carl Bosch in 1917.
Incredibly, had the duo not invented the process, we would only be able to produce two-thirds of the food we do now.
The Spanish Flu pandemic killed more people than World War I, wreaking havoc across the globe in 1918. Following the outbreak, British bacteriologist Fred Griffith sought to develop a vaccine. In 1928, he conducted the first experiment, demonstrating that bacteria can transfer genetic information.
Griffith's experiment inspired Rockefeller Institute researcher Oswald Avery (pictured), who headed the team that revealed in 1944 that DNA holds the genetic code.
Like its counterpart during the late 19th century, the Great Depression stimulated a wave of innovation. For starters, the mass-production car radio was invented in 1930 by Motorola founders Paul and Joseph Galvin, who needed an affordable product to keep their business going following the Wall Street Crash of 1929.
Entrepreneur Michael Cullen came up with the idea for a new type of "monstrous", mostly self-service grocery store while working at Kroger during the 1920s.
Cullen opened the world's first supermarket, King Kullen, in 1930 in the New York borough of Queens. As the Great Depression began to bite, thrift-conscious customers flocked to the outlet, and the rest is history.
Another Great Depression-era invention, the process that underlies the photocopier was dreamt up by physicist Chester Carlson during the late 1930s.
At the time, Carlson, like many Americans, was “living hand to mouth” and looking for a way to make his fortune. The innovator was eventually awarded a patent for his electrophotography technique in 1942.
Arguably, a far more important invention came about in 1943: the world's first programmable, electronic, digital computer. The Colossus Mark 1, as it was called, was designed in the most part by Post Office engineer Tommy Flowers in Dollis Hill, London and used to crack messages sent and received by German High Command. Shown here is the second version of the computer, the Colossus Mark 2.
World War II ushered in a plethora of trailblazing innovations. First up is cyanoacrylate, aka Super Glue. The exceedingly strong adhesive was discovered accidentally in 1942 by a team of Eastman Kodak scientists led by Dr Harry Coover, who were attempting to make clear plastic gun sights for the war effort.
The concept of an aerosol spray can was conceived as far back as 1790, and the first patent for the technology was issued in 1927 to Norwegian inventor Erik Rotheim.
But the first practical application of the innovation was only rolled out in 1943: a pressurised spray can packed with insecticide to protect Allied soldiers against malaria that was developed by USDA researchers Lyle Goodhue and William Sullivan.
While penicillin was famously discovered in 1928 by Alexander Fleming, the world's first antibiotic didn't enter into mass production until 1944 when Pfizer opened the first commercial plant in Brooklyn, New York.
That year, the US produced 1,663 billion units of the wonder drug. In the following 12 months, production skyrocketed, totalling an impressive 6.8 trillion units.
Jet engine technology was in its infancy at the beginning of World War II, but by the end of the conflict, the innovation was at the vanguard of aviation advancement.
The earliest models were developed in Nazi Germany. The first proper jet aircraft was the Heinkel He 178 (pictured), which debuted in 1939. It was followed by the Messerschmitt Me 262.
In 1945, American physicist Percy Spencer was touring a lab where microwave-generating magnetron tubes (the basic mechanism of radar during the war) were being produced when he noticed a peanut bar in his pocket had melted.
Intrigued, the scientist conducted several experiments that included creating the world's first microwaved popcorn. Spencer filed a patent for the technology. Two years later, the very first commercial microwave was launched.
Many important innovations came about during the Cold War. These included radio-frequency identification (RFID), which nowadays is used in everything from credit cards to library books.
The forerunner of the technology was a passive listening device called 'The Thing'. Designed by Soviet inventor Léon Theremin, the bug was hidden inside a wooden replica of the Great Seal of the USA in the Moscow office of the US Ambassador in 1945.
The fierce Cold War rivalry between the USA and USSR led to the so-called Space Race, with both countries accelerating their respective space programmes to outdo the other.
The Soviets won the initial leg of the race when they launched the world's first artificial satellite – the Sputnik I – in 1957. The technology has revolutionised communications, weather forecasting and more. Today, thousands of artificial satellites orbit our planet.
Much to the annoyance of the US government, the USSR pulled off a major coup in 1961 when cosmonaut Yuri Gagarin became the first human to fly in space.
Gagarin orbited the Earth for 108 minutes in the Vostok 1 spacecraft. In response, President John F. Kennedy committed to landing a man on the Moon by the end of the decade, a feat NASA pulled off in 1969.
Described by sci-fi author Isaac Asimov as “the most important moment since man emerged as a life form”, the invention of the mighty microchip by Texas Instruments engineer Jack Kilby at the height of the Cold War in 1958 was a major game-changer.
First developed for military purposes, the integrated circuit gave birth to modern computing. Today, it powers everything from smartphones to air traffic control systems.
The development of the internet also arose due to Cold War concerns, when the US military sought a computer communications system lacking a central core to protect against Soviet all-out cyber attacks.
As a result, the US Department of Defense created the Advanced Research Projects Agency Network (ARPANET) in the late 1960s, and this network evolved into the internet as we know it today.
Yet another crucial Cold War innovation, electronic mail was invented in 1965 at the Massachusetts Institute of Technology (MIT). The first computer-to-computer message was relayed via the ARPANET network in 1969, while the first proper email programme was created by Ray Tomlinson in 1971.
Of course, the technology didn't go mainstream until the 1990s.
The COVID-19 pandemic sparked a series of innovations, but one of the most significant was the development of the mRNA vaccine. Standing for messenger ribonucleic acid, mRNA is a component that, when used in vaccines, can send instructions to somebody's cells to produce an immune response to a particular protein that's identical to one found in a virus: in this case, COVID-19.
Pharmaceutical giants Moderna and Pfizer created the first and second mRNA products on the market respectively in the rush to develop a successful vaccine. They and other manufacturers are now applying the same biotechnology to create vaccines for other diseases.
Arguably the biggest cultural innovation to come out of the COVID-19 pandemic was the rise of remote working. Initially necessary to curb the spread of the disease, remote or hybrid work is now commonplace as employees adapt to doing their jobs outside the office.
By 2022, 25% of UK employees worked from home at least some of the time, according to Forbes – an increase from 4.7% in 2019. Meanwhile, a recent survey found that 40% of US workers would look for another job if they couldn't work remotely anymore.
Governments have historically been reluctant to give direct cash assistance to citizens, preferring instead to give aid in the form of vouchers. However, that all changed with the sudden dawn of the COVID-19 pandemic.
Widespread stimulus cheques and furlough payments were a lifeline to millions of people around the world. Since this form of support is much easier and quicker to administer than in-kind payments, these schemes have been credited with keeping economies (mostly) afloat during and after the crisis.
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