The Mongol empire stretched as far as Eastern Europe and the Middle East to the west, parts of Russia to the north, and China to the south. With a formidable army riding on horseback, lending much speed to the Mongols' conquest of many strong kingdoms and empires, and good military tactics, they were able to subdue a large portion of Asia, perhaps one of the largest empires in history. However, despite the size of the Mongol army, it struggled to conquer the tiny kingdom of Goryeo, the first unified dynasty of the Korean peninsula.

It took them more than 25 years to subjugate the small state, and eight invasions before finally breaking through to the royal family. What had the hermit kingdom done in order to fend off the largest empire at the time?

The Goryeo dynasty of Korea was established in 918, right after the Later Three Kingdoms period. For the next 300 years, Goryeo would experience incursions from the Khitan Liao, out of which they gained valuable insight on how to use the two-pronged strategy of the quill and the sword - diplomacy and military prowess - to successfully resist the 100,000-strong Khitan army.

So, when the Mongols came knocking on Goryeo's door, the Koreans did not go down without a fight. Now, by the first invasion in 1231, the Goryeo dynasty was still under the military aristocracy who had fortified the kingdom's defenses with well-trained soldiers. This was further bolstered by wise diplomatic withdrawals and peace negotiations to bide them time to prepare for the next attack.

The dynasty continued on with this quill-and-sword strategy until their dictator suddenly died thus weakening the control of the military aristocracy. Add to this the fact that the Mongols burned fields whenever they were able to subdue villages, Goryeo's royal family would later sue for peace and make an alliance with the Mongols.

(Image credit: History Maps)

Drug lord Pablo Escobar had a menagerie of exotic animals on his seven-square-mile Colombian estate called Hacienda Nápoles. When he was killed in 1993, most of the animals died or were taken to zoos. Escobar's collection of hippos, however, were just left in place. These animals are huge, ill-tempered, and dangerous, and they seemed to be getting along fine on their own. Thirty years later, the herd has grown to around 170 hippos, and they've been declared an invasive species in Colombia.

The Colombian government has announced a plan to try to control the hippo population, which could grow to a thousand animals by 2035 if left unchecked. They plan to capture some, kill some, and sterilize some. And now you're thinking the same thing I did when I read the headline: just how do you sterilize a hippopotamus? Not only are they huge, ill-tempered, and dangerous, they also have very thick skin and tend to stay in the water. Read about the plan to sterilize the hippos at Smithsonian.

(Image credit: Paul Maritz) 

In the 19th and early 20th century, people would walk backwards long distances in order to gain publicity or set a world record. It was akin to flagpole sitting- useless, but a way to make yourself famous. But maybe they were on to something. Studies of human physiology show that walking backwards, or "retro walking," has benefits for our health.

The main risk of walking backwards is the inability to see where you are going, but that can be overcome with a mirror, a partner, or a peeking technique. The actual act of walking -or running- backward is easier on the hip and knee joints because the range of motion is smaller. Also, you are using muscles that you normally wouldn't in forward locomotion, like back muscles. Walking backward has been shown to reduce pain in the lower back and strengthen hamstrings. The backward motion also causes you to land on the balls of your feet instead of the heel. The brain benefits, too, by using different brain areas to control the incongruous task. Read about the physical and mental benefits of walking backward at BBC Future.  -via Strange Company

(Image credit: Roberto Ferrari)

Nobody knows what airline company is operating a fleet of Boeing 737-600s which have no logo or name on it, except for a red line running through its side. It's dubbed the most secretive airline in the world, and some have named it Janet. But Janet is not really the name of the airline.

So, why is it called Janet? Apparently, it's an acronym which stands for 'Joint Air Network for Employee Transportation'. And it supposedly transports officers of the United States Air Force to Area 51. Not only that, but rumor has it, it's being housed in a secret terminal, which some have said is located in Las Vegas. 

Currently, Janet is looking for a new operator, and will host different players in the airline industry to acquire bids next month. Apparently, Janet also has its own Wikipedia page, so if you want to know more details about Janet's fleet or area of operations, you may want to go there to check them out.

(Image credit: Eddie Maloney/Wikimedia Commons)

Rules help maintain peace and order in society. They provide boundaries that protect us from doing harm due to some excessive behavior or action. At times, they are guidelines which could help us know what to do in certain situations.

However, in cases where there are no rules, it's difficult to determine to what extent we can do something, until somebody goes a bit too far prompting others to make rules against it. In this regard, people on Reddit shared what rules were made due to something they did.

The behaviors exhibited by these people were not ethically or morally wrong per se, it just bothered some people in authority. Some rules were a bit silly and funny like these two:

Others like this one seem to be necessary just to prevent any harm from befalling other people.

However, this rule made me crack up because it came out a misunderstanding, but the rule can be quite useful in the future, and really quite forward-thinking.

To see all 25 rules, check out Tastefully Offensive.

(Image credit: Mark Duffel/Unsplash; Tastefully Offensive)

People going on vacation sometimes go on a luxury cruise ship so that they can have a fun time at sea. It has a lot of amenities inside the ship, and you get to travel while on it. In the 1940s, Pan Am founder and CEO Juan Terry Trippe wanted a luxury airliner that would rival ocean liners, and so, he bought Boeing's most luxurious airliner at that time, the Boeing 377 Stratocruiser.

The Stratocruiser was a semi-double deck airliner which featured a cocktail lounge which could be accessed through a spiral staircase that led downstairs. It had bunk beds, spacious seats, a coat closet, and even dressing rooms for men and women. It would have been the perfect luxury airliner, until its propellers started falling off.

Despite having the more advanced R-4360 engines, the propellers were pushing the boundaries of the technology a bit too far. Several flights in the 1950s had suffered from engines dropping mid-flight and in April 1952, a Pan Am flight crashed into the Amazon rainforest when one of its engines and propellers tore off, killing everyone inside.

Pan Am crashed seven Stratocruisers from 1952 to 1959, and most of the others had been sold for scrap. Later on, the Boeing 707 became the new hot thing that airlines turned to, and with it began the dawn of the Jet Age. The junked Stratocruisers were later reused to build super-sized Guppies, which became cargo carriers for NASA's rocket parts.

(Image credit: Pan Am/HistoryNet)

Memes can come from anything as long as anybody finds a witty way to put words on a photo. Even the most mundane images or scenarios can be brought to life by memefying them, and putting another spin to the scene being depicted in the photo. Creativity is the key, as long as one has an eye for it, even the most obscure photos can become legendary. Just like these three military memes.

Of course, behind the memes that went viral online are real people who have encountered serious situations over their military career. The first meme is the "You don't operate, do you son?" featuring the retirement photo of former EOD specialist and Delta Force operator, Mike Vining. The second is the Grenade Meme, showing Chris DeBlanc, a Marine, who is casually throwing a grenade down a flight of stairs. The third is of Dan Pronk, a member of the Australian Special Air Service as a combat medic, who had been in Afghanistan doing a raid.

Despite these photos becoming viral on the internet, there's more to the stories of these three men than just those moments that were captured on camera. They share their stories as well as the tales behind the photos with Coffee or Die Magazine.

(Image credit: Mac Caltrider/Coffee or Die Magazine)

Queen Genepil was merely 18 years old when she was chosen by the Mongolian council to become the new wife of Bogd Khan. Her name was Tseyenpil and she was already married with children at the time, but the councilors had assured her that the marriage would just be for the sake of appearances as they merely wanted to maintain the image of the monarchy.

Had she refused the proposal, that would have been the end of it, and the councilors would have been forced to let the arrangement go. But Tseyenpil agreed and became the queen consort of the Bogd, and she was renamed Genepil. A year after their marriage, the Bogd died marking the end of the Mongolian monarchy.

Unfortunately, after the abolition of the Mongolian monarchy, the Mongolian People's Revolutionary Party took over and its leader, Khorloogiin Choibalsan, who had been referred to as the "Stalin of Mongolia", became the supreme ruler. Much like Stalin, he began purging Mongolia of people whom the party deemed as dissidents and enemies of the revolution.

Being a former queen consort, Genepil was accused, tried, and convicted of treason. She and her family were arrested in 1937, and a year later, executed. Despite this, her daughter Tserenkhand escaped the fate of her family and recalls how her mother had been taken at night and simply left a piece of sugar on their pillows.

(Image credit: Joy V Spicer)

Simone Segouin had only been 15 years old when the Germans invaded France, and for the next three years of her life, she helped her father shelter and feed the resistance fighters. She became acquainted with Roland Boursier who taught her how to handle rifles, explosives, and guerilla tactics. He gave her fake documents and a codename, Nicole Minet.

At the age of 18, she became a reconaissance agent for the French resistance by stealing a bike from the Nazis in Chartres, and pedaling around the area uninhibited. Later, having become an expert in the use of weapons and tactics, she led more daring operations against the Germans, capturing troops, setting traps, and sabotaging German equipment.

It soon escalated to bigger and riskier operations which included blowing up bridges and derailing German trains. Leading up to the liberation of France in 1944, she continued to fight with her comrades with a submachine gun slung on her shoulder until the joint forces of the French army, the US infantry, and the French resistance were able to retake Paris.

She became a second lieutenant and received the Croix de Guerre for her service in the resistance. She and Boursier had six children together although they didn't marry. After the war, she became a pediatric nurse in Chartres, and lived to be 97 before passing away this year on February 21st in Courville-sur-Eure.

(Image credit: US National Archives and Records Administration/Wikimedia Commons)

The 2023 Comedy Wildlife Photography Awards have been bestowed upon the funniest nature pictures of the year. Congratulations to Australian photographer Jason Moore, who was named the overall winner for his photograph titled Air Guitar Roo. The same photo won Alex Walker’s Serian Creatures of the Land Award. For his efforts, Moore wins a photo safari for two in Kenya, two camera bags, and a nice trophy. Not to mention global publicity and bragging rights. Let the Photoshopped memes begin! 

Jacek Stankiewicz of Poland won two awards with this picture he calls Dispute. It took the Junior category award plus the Affinity Photo 2 People's Choice Award. He figured the juvenile bird was either arguing with his parents, or else tattling on a sibling. See all the category winners and ten Highly Commended photos (I particularly like the Monday morning owl) in the winners gallery. 

The fairly new term "Anthropocene" refers to a proposed geologic epoch in which man made his mark on the earth. We are in that epoch right now, but when did it start? That's up for discussion. There are arguments that man began changing the world with the development of agriculture, but was that enough change to make a real difference? Was it the Industrial Revolution? Or maybe the first atomic bomb? No consensus has yet been reached.

There is a proposal to use Crawford lake in Ontario as a reference point for the beginning of the Anthropocene -or at least for studying and documenting it. It's a small lake, but it has some very specific and interesting properties that make it uniquely suitable for such a reference point. Besides it being perfectly suited for the purpose, it's already in a conservation area designated as an Ontario Area of Natural and Scientific Interest. Savannah Geary of Sci Show explains, and makes us want to visit Crawford Lake.

Once upon a time, a person's home was wherever they built it, and the places that didn't have homes were considered shared land. Then came the concept of purchasing private property and land grants and deeds, and poor people were out of luck. But in that transition period, people came up with schemes to work around that. One was the concept of tŷ unnos, a Welsh term meaning "house built in one night." It became a tradition that if one were to build an entire home in one night before the sun came up, they would own that house, plus however much land they could toss an axe to.

Young people would plan their adventures in building for a long time, making some components and gathering construction materials. Then on the planned night, all their friends and family would begin building when the sun set. These crude structures were merely four walls with a door and a roof, with a chimney because a fire was necessary. After the household was established, the tŷ unnos would be replaced by something more substantial. This tradition was not limited to Wales, though. A similar scheme existed under different names in Ireland, Italy, France, and in Turkey. Read about tŷ unnos and how that worked at Amusing Planet. 

(Image credit: Steve Daniels)

Since Disney's very first feature-length animated film, Snow White and the Seven Dwarfs, was released in 1937, Disney has had 62 animated films to date. We might like some more than others, but one thing is for certain - Disney has spread joy and the love of film and animation into the hearts of young and old alike.

When it comes to Disney's animated film canon, people have generally sectioned them off into various eras. Currently, we're in the revival era, which started in 2009, with The Princess and the Frog.

With a new Disney film coming out, Rolling Stone goes through all of Disney's 62 animated films to rank them. One can guess which films got into their top 10, as a majority of them come from either the golden era or the renaissance period, but a few other films that others don't consider to be top-tier Disney films also made it to the top.

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Looking for cheap tickets to your next travel destination can sometimes be like finding a needle in a haystack. Most tickets will be around the same price, and even the cheapest ones you can find will barely be within your budget. A few savvy travelers however, found that there's a very interesting workaround to get affordable airfare, but it might be very risky.

It's called skiplagging, and it's when you buy a ticket with a layover flights, but you hop off at your intended destination without boarding the connecting flight. It's a loophole with some serious consequences. Although it's not illegal, airlines strictly prohibit engaging in the practice since it will be a huge cost to them. If they catch people skiplagging, then they can either ban them from future flights, strip them of loyalty status, or have them pay the full price of the ticket.

Skiplagged is a website based on the concept of skiplagging. It's intended to help consumers find the cheapest flights to their destination. It was founded by Aktarer Zaman who noticed these cheaper layover flights, and so built an algorithm that searches for them.

There are a few caveats when skiplagging. You have to travel without checking your bags as those will be routed to the final destination on the ticket. And you can't do roundtrip tickets because it will get canceled for a no-show on the second leg.

(Image credit: Erik Odiin/Unsplash)

It seems inevitable that whenever we have holiday parties and family gatherings, we must make polite conversation with the relatives and guests to show proper etiquette. So, we try our best to make small talk, initiate the conversation, and keep it going. However, there comes a point when somebody comes up with some very personal and, at times, pointed questions which we would rather not answer. How then should we react without being flippant or rude about it? Communication experts suggest the swivel method.

The swivel method is basically pivoting away from the awkward topic by acknowledging it, showing appreciation and empathy, and then subtly moving on to another topic. It's a form of redirection that doesn't make the person feel as though they have stepped on a landmine. With the swivel method, you don't ruin the mood and you keep the momentum going.

Now, it's a different case if people continue to press you on those matters. Generally, people don't mean to put you in an awkward position. It's best to assume that they are well-meaning with their questions, just that they are unaware which questions cross boundaries. If, on the other hand, we find ourselves being the person others feel the need to swivel from, Debra Fine, an etiquette expert, suggests to never ask questions that we don't know the answers to.

(Image credit: Antenna/Unsplash)