US marines take part in a tactical exercise a few seconds after an atomic bomb. Many soldiers who were present were exposed to high levels of radiation

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Not long ago, there were no galaxies far, far away. In fact, less than a century ago, many scientists believed there was just one galaxy, the Milky Way. All that changed, however, on December 30, 1924, when astronomer Edwin Hubble announced he had evidence that the Milky Way galaxy was just one of the many galaxies in an ever expanding universe.

Discovering that our galaxy wasn’t alone was just the beginning for Hubble. He continued measuring distances and velocities in deep space, finding that the further apart galaxies are from each other, the faster they move away from one another. His findings, published in 1929, led to the widely accepted notion that the universe is expanding. Albert Einstein personally thanked Hubble for the support his findings gave to his theory of relativity.

Earlier, in 1917, Albert Einstein had found that his newly developed theory of general relativity indicated that the universe must be either expanding or contracting. Unable to believe what his own equations were telling him, Einstein introduced a cosmological constant to the equations to avoid this "problem". When Einstein learned of Hubble's redshifts, he immediately realized that the expansion predicted by General Relativity must be real, and in later life he said that changing his equations was "the biggest blunder of his life".

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Albert Einstein with Edwin Hubble, in 1931, looking through the lens of the 100-inch telescope 🔭 through which Hubble discovered the expansion of the universe in 1924

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Alexander Fleming accidentally discovered the antibiotic penicillin in 1928, these natural inhibitors of microbial growth have revolutionized medicine and saved countless lives @facethenation

Fleming returned to his lab from vacation and noticed mold growing in a petri dish. There were no bacteria in the area around the mold because something in the mold was killing them

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A monowheel is one big wheel with rider and engine inside its circumference. The first monowheel designs appeared as early as 1869.

In the early 1900's, a group of American inventors attempted to develop a propeller-driven monowheel. Monowheels were also built in Europe. The Italian inventor Davide Cislaghi designed a monowheel with a tilting outer wheel for turning. He received a French patent for the device in 1924 and a British patent in 1927. Historical accounts indicate that he went on to commercialize production of his design under the Motoruota name.

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Italian inventor Davide Cislaghi driving his monowheel motorcycle in France, 1935

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In 1864 Otto von Bismarck initiated decisive wars with Denmark, Austria and France to unite 39 independent German states under Prussian leadership @facethenation

Germany became a modern, unified nation under the leadership of the "Iron Chancellor" Otto von Bismarck, 1890

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Henry Ford was born on a farm family in Dearborn, Michigan. Henry himself did not like farming, but he did like fooling around with machines. Henry liked to fix all the farm machines, and he was known around the area to be a handyman. So as a youth Henry fixed various machines for surrounding farmers. This hobby of Henry's made his father angry, he would neglect all of his farm chores.

When he was 16, Henry left to work in nearby Detroit as an apprentice machinist. After completing his apprenticeship in 1882 he returned to his father's farm. A neighbor, John Gleason, paid him $3 a day to operate a small portable steam engine that cut corn, ground feed, and sawed wood. Ford's ability came to the attention of the district representative of the Westinghouse Engine Company of Schenectady, New York, and he was hired late in the summer of 1882 to travel throughout southern Michigan setting up and servicing Westinghouse steam traction engines.

In 1913 Henry Ford began searching for that little steam-engine. All he knew was its number, 345. After a long hunt it was found on a farm in Pennsylvania, rusty with disuse. The number plate was found in the farmhouse kitchen, used as a patch on an old cookstove. The farmer wanted ten dollars for the worthless thresher. Ford paid it and gave him a new Model T as a bonus; and he threshed again with the old steam-engine in Dearborn on his sixtieth birthday

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Henry Ford with Westinghouse Steam Engine No. 345 in Dearborn on his sixtieth birthday

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General Eisenhower speaks with the 101st Airborne Division just before they board their planes to participate in the first assault of the Normandy invasion on June 5, 1944 @facethenation

Eisenhower, giving the final order for D-day, the assault on Nazi-occupied France. It was the beginning of a campaign of of liberation of Europe from nazi tyranny

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The lumberjacks of the 1800s performed their difficult and dangerous work without any of the conveniences of modern technology. They used axes and long, flexible saws known as "misery whips". Daily pay of around $1.25 and tools such as steel wedges, sledgehammers, and log-moving tools, made logging a perilous and underpaid profession.

Up until the 1880s, lumberjacks felled trees with axes. Lumberjacks used two types of axes: a single-bitted or single-headed axe and a double-bitted axe. Some loggers believed the double-bitted axe to be a dangerous choice, and preferred to use two single-bitted axes instead. They would use one axe to get through the bark and the second for the tree itself.

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Lumberjacks undercut a Giant Sequoia tree 25 feet in diameter in Northern California, 1902 @facethenation

President Richard Nixon visits the Apollo 11 astronauts. After returning from the Moon astronauts were quarantined in case they had brought unknown pathogens back to Earth, 1969 @facethenation

Richard Nixon applauds the returning Apollo 11 astronauts, Neil Armstrong, Michael Collins and Buzz Aldrin

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Detroit, Michigan, 1907 @facethenation

In 1912 Glenn Curtiss developed his famous flying boat and in 1919 his NC4, developed for the US Navy, became the first airplane to cross the Atlantic Ocean @facethenation