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1.
Fatal Familial Insomnia — An extremely rare genetic neurological disorder that causes progressive insomnia, leading to total sleep deprivation and death.
At the most basic level, FFI affects the part of the brain that controls sleep. People with this rare disorder slowly lose the ability to sleep, and this leads to serious problems like confusion, trouble moving, body changes (like sweating a lot or having a fast heartbeat), and eventually death — usually within a year or two. Currently, there is no cure or treatment. Doctors can test for the gene, but they can only treat the symptoms to keep the person as comfortable as possible.
2.
Guatemala Syphilis Experiments — Unethical medical studies conducted by the US government in the 1940s, where researchers intentionally infected prisoners, soldiers, and mental patients in Guatemala with syphilis and gonorrhea without consent.
Without the people’s knowledge or permission, researchers deliberately infected hundreds of Guatemalan prisoners, soldiers, sex workers, children, and even mental hospital patients with syphilis and other sexually transmitted diseases to test if antibiotics like penicillin could prevent or treat them. Many of the people were never treated, and some suffered serious health problems or died. These experiments were kept secret for decades and only became public in 2010, when the U.S. government formally apologized for the abuse and wrongdoing.
3.
Unit 731 — Japan’s WWII biological and chemical warfare research unit that conducted live human experiments.
Unit 731 was a covert biological and chemical warfare unit of the Imperial Japanese Army during World War II, based in occupied Manchuria (present-day China). Operating under the guise of epidemic prevention, it conducted brutal human experiments on civilians and prisoners of war, including vivisection, forced infection with deadly diseases, and frostbite testing. These experiments led to the deaths of an estimated 300,000-plus people.
After the war, the U.S. granted immunity to many Unit 731 members in exchange for their research data, allowing key figures like Ishii to avoid prosecution. The unit’s atrocities remain one of the most horrifying examples of wartime human experimentation.
4.
The Monster Study — A 1939 unethical speech experiment that was conducted on orphaned children in Iowa. Some were psychologically abused to induce speech problems.
Led by a researcher named Wendell Johnson, this controversial experiment set out to find out if telling kids they had a speech problem could actually make them stutter. They worked with 22 children from an orphanage — some who already stuttered and some who didn’t. The researchers told some of the kids with normal speech that they spoke badly and needed to be careful, even though that wasn’t true. As a result, some of those kids became shy, nervous, and had trouble speaking, even though they hadn’t stuttered before. The experiment caused lasting emotional harm, and it was later called the “Monster Study” because of how unethical it was. In 2007, a lawsuit filed by former test subjects and estate representatives of those who have since died was settled for $925,000.
5.
Radium Girls — A group of young women in the 1910s and 1920s who worked in factories painting watch dials with glowing paint that contained radium, a radioactive element, ultimately leading to their horrifying deaths from radiation.
The young women were told the paint was safe and were even encouraged to lick their brushes to get a fine point. Over time, many of them became very sick — losing teeth, suffering from broken bones, and developing terrible jaw problems — because the radium was poisoning them from the inside. When the companies refused to take responsibility, some of the women fought back by taking them to court, winning a settlement in 1928.
6.
FOP (Fibrodysplasia Ossificans Progressiva) — An extremely rare condition where a person’s soft tissues — like muscles, tendons, and ligaments — slowly turn into bone over time, essentially turning people into “living statues.”
Because of this condition, parts of the body that are supposed to move and bend can become locked in place by extra bone growing where it shouldn’t. Even small injuries, like bumps, can trigger this bone growth. As FOP gets worse, it can become very hard to move, eat, or even breathe because of extra bone forming around the rib cage, restricting expansion of the lungs. There’s no known cure yet, and doctors try to help by avoiding anything that might cause flare-ups and by managing symptoms as best they can.
7.
Tuskegee Syphilis Study — A racist and unethical 40-year medical experiment carried out by the U.S. government where Black men with syphilis were deliberately left untreated.
From 1932 to 1972, the Tuskegee Syphilis Study involved hundreds of poor Black men in Alabama who had syphilis but were never told they had the disease. Instead of treating them, doctors studied how the illness would progress if left untreated — even after penicillin became the standard cure in the 1940s. The men were misled and denied proper care for decades, which caused serious harm and death. The study only ended after a news report exposed it, leading to public outrage and a formal government apology in 1997.
8.
Teratoma — A type of tumor that commonly contains teeth, hair, fat, or muscle. They can even contain a liver, lungs, eyes, or even a brain, though it’s not as typical. Teratomas are sometimes mistaken for parasitic twins.
This type of tumor happens when certain cells that are supposed to develop into any part of the body grow in a confused or mixed-up way. Teratomas can be found in places like the ovaries, testicles, or even the chest or brain. Most are harmless and can be removed with surgery, but some can be cancerous and need more serious treatment. Even though they can sound strange or scary, many teratomas are treatable, especially when found early.
9.
MKUltra — A highly secretive human CIA experimentation program that tested mind control techniques, often without subjects’ consent.
MKUltra began in 1953 and ran through the 1960s. The program consisted of a series of projects that experimented with mind control techniques — often without people’s knowledge or consent. They tested drugs like LSD, hypnosis, and other methods on prisoners, hospital patients, and even regular citizens, hoping to learn how to control thoughts or extract secrets. Many people were harmed, and some were permanently affected or died. The project was kept hidden until the 1970s, when it was exposed by journalists and government investigations.
10.
Body Integrity Dysphoria — A rare condition where a person feels like a part of their own body — such as a leg, arm, or even their vision or hearing — doesn’t belong to them, sometimes giving them a desire to amputate healthy body parts.
Even though the body part is healthy, the person might feel very distressed and strongly believe that they would feel better or “whole” if it were removed or disabled. This condition is not well understood, and it can be very upsetting for those who experience it. Treatment is challenging, and doctors usually try to help through therapy and support, rather than surgery, since the condition is more about how the brain sees the body rather than something physically wrong.
11.
Exploding Head Syndrome — A harmless but startling condition where a person hears a sudden loud noise — like a bang, crash, or explosion — just as they’re falling asleep or waking up.
Even though it sounds real, there’s no actual sound and nothing is physically happening when people experience this. It doesn’t cause pain, but it can be scary and confusing. Some people also see flashes of light or feel a jolt in their body. Experts aren’t sure exactly what causes it, but it may be related to how the brain shuts down for sleep.
12.
Lobotomy — A once-popular psychosurgery technique involving destruction of the brain’s frontal lobe, often resulting in severe personality changes.
Though it’s since been discredited, at the time, this brain surgery was used to treat severe mental illnesses like schizophrenia and depression. It involved cutting connections in the brain’s frontal lobes to reduce symptoms, but often caused serious side effects such as personality changes, cognitive impairment, and emotional dullness. Popularized in the 1930s through to the 1950s — especially by neurologist Walter Freeman’s “ice-pick” method — it was eventually abandoned due to its harmful effects and the rise of psychiatric medications.
13.
Resignation Syndrome — A rare and mysterious condition where children, usually refugees, fall into a coma-like state after experiencing extreme stress or trauma — often related to uncertainty about asylum or fear of deportation.
Children with this condition will stop talking, eating, walking, and responding to the world around them, as if they’ve completely shut down. It has mostly been seen in Sweden among children from war-torn countries. Recovery can take months or even years, and often begins once the family’s asylum situation becomes more secure.
14.
Necrotizing Fasciitis — Also known as “flesh-eating bacteria,” is a rare but very serious bacterial infection spreads rapidly and is often fatal.
Necrotizing fasciitis spreads quickly and destroys the body’s soft tissue, especially under the skin. It’s sometimes called a “flesh-eating disease,” though the bacteria don’t actually “eat” flesh — they release toxins that kill tissue. It often starts from a small cut, bruise, or surgery site and can rapidly cause swelling, severe pain, redness, and fever. Without fast treatment, like antibiotics and surgery to remove dead tissue, it can become life-threatening.
15.
Harlequin Ichthyosis — A very rare and severe genetic disorder where babies are born with thick, hard skin that forms large diamond-shaped plates separated by deep cracks.
This tight skin can pull on the eyelids, lips, and chest, making it hard to move, eat, or even breathe. It’s caused by a gene mutation that affects how the skin forms a protective barrier. Babies with this condition are at high risk for infections and dehydration. While it was rare for affected infants to survive the newborn period with this condition, today babies with it now have a much better chance of living to childhood and early adulthood.
16.
Morgellons — A controversial and poorly understood condition where people feel like they have bugs crawling on or under their skin and often report finding strange fibers or particles coming out of their skin.
For people affected by this condition, these symptoms are usually very distressing and can include itching, sores, and pain. Many doctors believe Morgellons is linked to a mental health condition called delusional parasitosis, where a person mistakenly believes they’re infested with parasites. However, some patients and researchers argue it’s a physical illness that hasn’t been fully explained yet.
17.
Brain-Eating Amoeba (Naegleria fowleri) — Sometimes called the “brain-eating amoeba,” it is a rare but deadly microscopic organism found in warm freshwater like lakes, hot springs, and poorly maintained pools.
This amoeba can enter the body when water goes up the nose — usually during swimming or diving — and then travels to the brain, causing a severe and often fatal infection called primary amebic meningoencephalitis (PAM). Symptoms start with headache, fever, and nausea, and quickly progress to confusion, seizures, and coma. It’s almost always fatal, but very rare, and you can’t get it from drinking water — only from water entering the nose.
18.
The Thalidomide Scandal — A major medical disaster in the late 1950s and early 1960s, where a drug called thalidomide was given to pregnant women to treat morning sickness and help with sleep, but actually caused birth defects.
At the time, the drug was thought to be safe, but it caused severe birth defects in thousands of babies across the world. Many were born with shortened or missing arms and legs, and some had problems with their ears, eyes, or internal organs. It took five years for the connection between the drug and the birth defects to be made. The tragedy led to stricter drug testing and approval rules in many countries, especially during pregnancy.
19.
Randy Gardner sleep deprivation experiment — Randy Gardner was a high school student who, in 1964, stayed awake for 11 days straight (264 hours) as part of a science fair experiment — the longest scientifically recorded period of sleep deprivation.
During the experiment, he experienced mood swings, memory problems, trouble concentrating, and even hallucinations, but surprisingly had no long-term health effects. Researchers used the experiment to learn more about how important sleep is for the brain and body. Afterward, Randy recovered by sleeping for about 14 hours and then returning to a more normal sleep pattern.
20.
Trepanation — The oldest surgical procedure known to man, which was the practice of drilling or cutting a hole into the skull to treat head injuries, relieve pressure, or for spiritual reasons.
Evidence shows trepanation (trepanning) was practiced over 7,000 years ago in many ancient cultures. Surprisingly, some people survived multiple procedures. Today, it has evolved into modern craniotomy — a safer, more precise surgery used to treat brain injuries, remove tumors, or relieve pressure, performed with sterile tools and medical imaging.
21.
Finally, Biosphere 2 — A sealed greenhouse-like structure built in Arizona in the early 1990s to test whether humans could live in a self-sustaining environment, like a mini Earth, for space travel. Although it sounded cool, people ended up starving and “gasping for breath.”
Inside, the structure had different ecosystems — like a rainforest, ocean, and desert — and was meant to recycle air, water, and food for eight people living inside for two years. While the idea was exciting, the experiment faced major problems: oxygen levels dropped significantly, food became scarce, and people argued, making it hard to live and work.
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