| 1223 | In France, Louis VIII succeeds his father, Philip Augustus. | |
| 1430 | Joan of Arc, taken prisoner by the Burgundians in May, is handed over to Pierre Cauchon, the bishop of Beauvais. | |
| 1456 | Hungarians defeat the Ottomans at the Battle of Belgrade, in present-day Yugoslavia. | |
| 1536 | France and Portugal sign the Treaty of Lyons, aligning themselves against Spain. | |
| 1789 | The Bastille, a fortress in Paris used to hold political prisoners, is stormed by a mob. | |
| 1798 | The Sedition Act is passed by the U.S. Congress. | |
| 1864 | At Harrisburg, Mississippi, Federal troops under General Andrew Jackson Smith repulse an attack by General Nathan Bedford Forrest. | |
| 1900 | European Allies retake Tientsin, China, from the rebelling Boxers. | |
| 1933 | Nazi Germany promulgates the Law for the Protection of Hereditary Health–the beginning of the Euthanasia program. | |
| 1938 | Howard Hughes and crew set a new world record for an around-the-world flight. | |
| 1940 | A force of German bombers attacks Suez, Egypt, from bases in Crete. | |
| 1941 | Vichy French Foreign Legionaries sign an armistice in Damascus, allowing them to join the Free French Foreign Legion. | |
| 1945 | American battleships and cruisers bombard the Japanese home islands for the first time. | |
| 1951 | The George Washington Carver National Monument in Joplin, Missouri becomes the first national park honoring an African American. | |
| 1964 | The United States sends 600 more troops to Vietnam. |
Recorde's symbol didn't catch on at first. The language of Latin still held sway during the 16th century. Latin had a word for the concept, "aequalis," and if more concision was necessary, people could shorten it to "ae" or "oe." But aiding the popularity of the equals sign was Recorde's introduction, to English-speakers, of the German symbols "+" and "-". In combination, these signs allowed people to express, quickly and with a minimum of wasted ink, a mathematical equation in symbols. Instead of writing, "A factore added to a quantitie of thryeye is equalle to a dyffyrynte factore frome whyche is takene awaye a quantitie of foure," a mathematician could write: "x + 3 = y - 4".That opened the door for math to have its own language, understandable by people all over the world. Read about the remarkable Recorde and his legacy at Ars Technica.
An Oregon man has been arraigned on hate crime charges for threatening a Muslim couple only days after two men were stabbed to death in Portland after trying to stop an anti-Muslim rant. 
Unfortunately for Fossil Cycad, its official recognition as an American landmark came at a difficult time for the country overall. “It was a period of economic hardship,” says Santucci. “Fossil Cycad wasn’t really developed like other national parks and monuments were.” That meant no one was hired to watch over the land. While the superintendent of nearby Wind Cave National Park was put in charge of its overall management, “day-to-day surveillance was entrusted to local ranchers,” writes Santucci. The site’s only sign—a 15-inch carved wooden plank—abbreviated both “National” and “Monument,” but made sure to spell out “NO PROSPECTING.”And that is why you've never heard of Fossil Cycad National Monument. Read about the life and death of the national park at Atlas Obscura.
Despite this lack of amenities, tourists continued to swing by, and to take pieces of the monument home with them. “People reading in newspapers about the monument in the Black Hills would come,” says Santucci. Natural erosion meant that new layers of fossils were gradually exposed, creating more buzz and more foot traffic. Such was the Fossil Cycad catch-22: when there weren’t any visible fossils, it wasn’t much of a monument. But whenever there were enough to attract visitors, those same visitors meant they were quick to disappear.
Fire
ants, when trapped, will build a tower of ants in order to escape.
Researchers at Georgia Tech, instead of looking for ways to kill the
invasive insects, studied the architecture of ant towers. David Hu and
Craig Tovey observed how ants at the bottom supported the weight of
those above, and how ants reaching to top of the tower stopped to let
others crawl on top of them. They left a video recorder on for an hour
after the tower was completed and went to do something else. Later, not
wanting to watch an hour of ants, they viewed the video at ten times the
normal speed. That's when they discovered that the completed tower kept
sinking, and had to be constantly rebuilt.To confirm the sinking behavior, Tovey and Hu contacted experts at at Lawrence Livermore Labs and other institutes. They were told that the technology did not exist to track individual particles in the interior of a three-dimensional object, at the time and size scales of ant-made towers, without killing the insects. But when they talked to an expert at Georgia Tech, they were referred to Daria Monaenkova, a postdoctoral researcher working in Dan Goldman’s physics lab. Monaenkova, who would subsequently become a co-author of the new study, happened to be working on an x-ray technology that would enable the researchers to peer inside the ant tower itself.And that's where the story gets really neat. They actually fed radioactive iodine to some of the ants in order to track them by X-ray in real time to confirm the sinking tower. They determined that it was because the ants at the bottom understandably got tired and left. You can read the story and see both the original video and the X-ray version at Gizmodo.
