Leonardo da Vinci's masterpiece known as the Mona Lisa is the world's most famous painting. As such, you might be surprised to find out it's a rather small portrait, and so many people go to the Louvre to see it that you can't really get close enough to study it. But that's okay, because we have plenty of photographs. We can admire her smile, her eyes, and ...where's her eyebrows? Did Lisa del Giocondo, the model for the portrait, have her brows plucked out? Or did Leonardo just leave them out of the picture? 

August Moon takes us through serious research on the subject of the Mona Lisa's eyebrows, and what they are supposed to look like. In the process, we find that many of the world's greatest paintings are not what they seem on the surface. That surface is constantly being messed with in the hopes of keeping the paintings clean and undamaged, which still ends up damaging them. And we get a lesson in what really makes the Mona Lisa such a unique and memorable portrait.  -via Laughing Squid 

When Spain conquered Mexico, it opened up trade in all sorts of previously unknown products from the New World. One was Lignum nephriticum, a type of wood that, when soaked in water, would produce a tincture useful for treating kidney and urinary ailments. Lignum nephriticum literally means kidney wood. Physician Nicolás Monardes first described the wood in 1569. He couldn't describe the plant it came from, though, because he'd never been to Mexico. Monardes wrote about soaking wood chips in water, and seeing the water turn blue. But then other Europeans described a different result. When the wood chips were soaked with water in a cup made of Lignum nephriticum, the water turned blue, yellow, orange, and red depending on the light! The liquid could even display more than one color at once.

Scientists of the time were more interested in the colors than they were with the wood's medicinal value. But why were the descriptions so different? Could Mexico have more than one type of kidney wood? For one reason or another, no one put too much energy into solving the mystery until the 20th century. Read about the real origins of Lignum nephriticum at Jstor Daily. -via Strange Company 

(Image credit: Safford, William Edwin) 

We think of camouflage as what animals use to blend in with their background. A ship that has zebra stripes that aren't even straight is not what a normal person would call camouflage. But a still photo doesn't do it justice, because ships are always in motion, and the enemy is looking for a ship in motion. If a ship sits still, it's probably not in a battle zone. 

Razzle Dazzle camouflage was developed in World War I in response to submarines attacking them with torpedos. In order to understand the mechanism behind the idea, we have to put ourselves in the place of an enemy submarine aiming a torpedo. The bedazzled ship doesn't have to be invisible; it just has to be hard to destroy. Did it work? Not as well as hoped for, but any edge is worth the effort to save a battleship and its huge crew. Half as Interesting takes us through the steps behind the design. The camouflage ends around 5:35; the rest is an ad for a good cause. 

The JJ Walser House in Chicago was designed by Frank Lloyd Wright and built in 1903. The home is on the National Register of Historic Places and is designated a Chicago Landmark. Nevertheless, it is falling apart. The longtime owner died in 2019 and her family discovered she had taken out a mortgage to fix the roof. They couldn't afford the payments, so the home is in foreclosure. Since it has been unoccupied for six years (except for squatters), the house is deteriorating rapidly. 

Someone recently listed the house for sale at Zillow for far above the actual value, and drew the attention of the Frank Lloyd Wright Building Conservancy. The listing was deemed a fraud and was removed, but the images show how far the home has fallen. The Walser house is being auctioned by Fannie Mae. Various conservancy groups are interested, but none can afford the expensive repairs in addition to the purchase price. 

Frank Lloyd Wright is the most famous architect America has ever produced. His buildings display clean lines and beautiful details. Yet no one wants to actually live in his houses, since they are form over function. The flat roofs leak, the doorways are too short, and the lovely ledges and stairs are dangerous. Read the story of the Walser House at Dwell. -via Metafilter 
 
(Image credit: Zol87) 

Someone observed that when a chocolate ice cream cone sideswipes a vanilla ice cream cone, both of them end up with a bit of each other. Others of the TikTok generation rushed out to replicate the experiment because, hey, ice cream! James Orgill of the Action Lab (previously at Neatorama) explains why they don't just mix together and why it's always both cones involved.

I must admit he almost lost me in the middle of the video. I understand laminar flow, but not so much quantum physics and Heisenberg's uncertainty principle. But hang on, because all he's explaining there is what's not happening. Then he compares the two ice cream cones to planets colliding and it all becomes clear. Still, all I could think of during this video is the old Reece's campaign: "You got your peanut butter on my chocolate! You got your chocolate in my peanut butter!" Because after all, these ice creams are two great tastes that taste great together.   

You can buy all kinds of memorabilia on eBay, often for a pittance. It takes a good eye and often meticulous research to know if it has historical significance, a task way beyond volume sellers. In 2010, space historian and collector Robert Pearlman paid $5.50 for a bundle of "remove before flight" tags. These are tags attached to parts of aircraft like pins and covers that are protective on the ground, but must be removed in order for the aircraft to function. He intended to use the tags, listed as from the space shuttle program, as giveaways. 

About a year later, Pearlman decided to check out the numbers on the tags. Such tags are labeled so they can be inventoried before flight to make sure each component is removed. By cross-referencing the numbers with NASA records, he found the tags were removed from the doomed space shuttle Challenger before it exploded soon after launch 40 years ago this week. But NASA was in flux at the time, and Pearlman had no luck in finding out more about the journey the tags took from NASA to eBay. He hopes to trace their story before donating the tags to a museum. Read his account of these tags so far at Ars Technica. -via Damn Interesting 

(Image credit: collectSPACE) 

Valentine's Day is the perfect day for a perfect date, right? If you want to impress your sweetheart, you'll want to go all out. If you're just getting to know each other, a movie is not the best idea because it's two hours of no conversation or physical activity. So  how about a nice romantic dinner at a nice restaurant? The Takeout has 11 Tips For Picking The Best Restaurant For Valentine's Day. These tips are a bit depressing. If you want to eat at the nicest places, better make your reservations now, but be aware that on February 14th, a Saturday this year, all restaurants will be crowded. You can avoid the crowds by eating early, but how romantic is 4 o'clock dinner? It's enough to make you prefer eating at home. 

Making dinner at home can be fraught with peril, too. What do you cook? That's up to you, but the Takeout has a list of 11 Things To Avoid Eating On Valentine's Day. Almost all the foods you'd expect to serve on this occasion are there. If you're in a long-term relationship, count yourself lucky because you can stay home on Valentine's Day and watch a movie while eating pizza, and maybe eat out on a less-crowded day.  

The coolest weapon in the Star Wars universe is the lightsaber, even cooler than the death star. It's a high-tech plasma laser, but you can swing it like a sword and show off your swashbuckling skills. The real genius of the lightsaber is that you can kill all kinds of people on film and never have to spill any fake blood (or clean it up). The ability to sell a ton of them as cool toys is a bonus. The best fictional weapon ever. 

Lightsabers come with an in-universe explanation, which is that the business end is made of superheated ionized gas, or plasma. It would be hotter than the surface of the sun. In the real world, such a weapon would be impossible to train with, too dangerous to wield, and its actual use in battle would probably be a war crime. YouTuber Mr. Death explains in gruesome detail what a lightsaber wound would do to you. The good news is that such a weapon isn't at all feasible in the real world. -via the Awesomer 

Anyone who's ever tried to make it in Hollywood knows that every rejection makes you more desperate. You notice that those who get the really good roles either had existing connections in the business, or they cut corners, like lying about their experience or abilities. So what if you tell a casting director that you can ride a horse, speak German, or play the drums? If you get the role, you can learn those skills in a hurry. It's a little harder to pull off being a few inches taller than you really are, or being in a production that casting director knows very well. These are all true stories. 

Actresses often lie and say they are younger than they are. Mila Kunis, on the other hand, got her role in That '70s Show after she told the producers she was "almost 18," which is a strange way to say you are 14. The show was well into its run when the truth came out. Read about 15 actors who fudged a little -or a lot- when auditioning for a role that they became well-known for at Cracked. 

Tuesday morning, a NASA pilot managed to set down a WB-57 aircraft at Ellington Airport in Houston after the landing gear failed to deploy. With no brakes, it had to be a butt-puckering experience, but no one on the crew was injured. Luckily, the runway was longer than the video. 

The WB-57, also known as the Martin B-57 Canberra, is a superlative plane. The B-57 was the first jet that could cross the Atlantic without refueling, and made the trip in just four hours and 40 minutes in 1951. It was used extensively as a bomber in Vietnam. The WB-57 variant could fly at altitudes up to 62,000 feet. That's why, when the Air Force phased out the plane, NASA snapped up the remaining three WB-57s in America. They are used for high-altitude research like collecting near-space samples and observing spacecraft launches. Read more about the WB-57 at Ars Technica. -via Fark 

A few weeks ago, we brought you the story of the unmade 1970s Star Trek revival series known as Phase II. But even before that, Star Trek was supposed to return as a feature film titled Star Trek: Planet of the Titans. Paramount saw the continuing interest in Star Trek when fans got the first NASA Space Shuttle named Enterprise. After plenty of discussion, they agreed to devote $10 million dollars to a feature film (a big budget at the time) that would begin filming in early 1977. 

The producers envisioned a Star Trek movie with the visual quality of 2001: A Space Odyssey. The story would be centered around Mr. Spock, and explore his struggles with his human side. Time travel was involved, and became the "twist" in the story. As more people became involved, the plot and focus changed, but the story was ready to go as 1977 came around. Then the project was suddenly canceled because "there’s no future in science fiction." That year, Star Wars and Close Encounters of the Third Kind took over movie screens. Read what Star Trek: Planet of the Titans could have been at Woman's World. -via Damn Interesting 

Ryan George, who has several video channels, took some time off and came back blonde. But he hit the ground running, with a video that combines two things we enjoy very much: dreaming of a tropical paradise (nice when you're snowbound) and roasting mega-expensive real estate. If you're one of the few people who can afford a multi-million dollar property in Hawaii, he's making fun of you, too. 

This video explores five homes on the market in Hawaii. They are gorgeous on the surface, but George focuses in on the details most people would miss, and constructs a complicated backstory to explain why they are so bizarre. Why would you build a bay window overlooking the ocean, and then furnish it so that every seat is facing away from the window? The rich are not like you and me. But then again, someone is selling these homes, so maybe it's because they aren't that rich anymore. 

People will try anything to be more attractive, and through most of history, the long-term effects of those beauty regimens were unknown. Sure, Aunt Sarah got sick and died young, but no one knew that it was the lead in her face-whitening makeup that did her in. Lucky for us, science eventually figured that one out. The further back you go, the more bizarre some of these regimens get. Ancient Greeks and Romans sometimes used urine as a mouthwash, because the ammonia it contained would eliminate worse smells. Eww. 

Also in Rome, a tincture of nightshade might be used as eyedrops, because they would dilate one's eyes. This could be very alluring, but it could also cause you to go blind or even die. There's a reason it came to be called "deadly nightshade." Read about ten of these deadly bygone beauty tips at Mental Floss. And then wonder what we are doing today that may be found quite dangerous in the future. 

Screen Junkies celebrates the silver anniversary of The Lord of the Rings movies, or at least the beginning of the trilogy, by giving us a full set of Honest Trailers in conjunction with the release of the extended versions of all three films in theaters. We've seen what they think of The Fellowship of the Ring and The Two Towers, and it's time for the big one: The Lord of the Rings: The Return of the King. 

Everyone from the previous installments shows up for the final battle, plus many characters we've never seen before. Everyone either dies gruesomely or gets to be the hero. The satisfying ending is not the end, and neither is that one. Or that one, either. The extended edition runs four hours and 23 minutes, so you wonder how many more ending scenes were tacked on. But you'll get plenty of Monty Python references and jokes at the expense of farts, George RR Martin, and England. 

In 1848, obstetrician Ignaz Semmelweis suggested that doctors should wash their hands between patients, and was laughed at. Then doctors started learning about germ theory, and medical sanitation rose, especially in surgery, where the danger of infection was particularly high. 

Dr. William Stewart Halsted, a prominent surgeon at Johns Hopkins Hospital in Baltimore, insisted that his entire surgical team not only wash their hands, but douse them in various germ-killing chemicals. Those chemicals caused massive irritation on the sensitive hands of his top assistant, nurse Caroline Hampton. So in 1889, Halstead had a couple pairs of rubber gloves custom-made for her. This was for Hampton's protection, not the patient's, but post-surgical infections dropped as more of his team started wearing rubber gloves. Some doctors rebelled against the gloves because they would surely affect sensation and fine motors skills, but that argument was eventuallyput to rest by improving the gloves. Read about the genesis of surgical gloves at Amusing Planet. 

(Image credit: Wellcome Collection)