In 1796, English doctor Edward Jenner noticed a local belief that milkmaids who caught cowpox, a usually mild disease, seemed protected from smallpox, one of history’s deadliest infections. He tested the idea by taking material from a cowpox sore on milkmaid Sarah Nelmes’s hand and inoculating eight-year-old James Phipps.

James became mildly ill, recovered, and later did not develop smallpox when Jenner tested whether the cowpox exposure protected him. The experiment was ethically unacceptable by modern standards, but it demonstrated the principle behind vaccination: safely training the immune system to recognize a dangerous disease.

Jenner did not invent the broader idea of inoculation, earlier practices such as variolation already existed but his cowpox-based method was far safer and became the first successful vaccine. The word “vaccine” itself comes from vacca, Latin for cow.

Almost two centuries later, worldwide vaccination campaigns led the World Health Organization to declare smallpox eradicated in 1980, the only human disease ever eradicated globally.

In December 1996, 12-year-old Celina Mays went to bed after church at her family’s home in Willingboro, New Jersey. She was nine months pregnant and due to give birth within weeks. By morning, she was gone, her blankets had been arranged over pillows to make it look as though she was still asleep, while her purse, prenatal vitamins, and other belongings remained behind.

No one has ever publicly identified the father of Celina’s baby. Her family said she had mentioned a 16-year-old boy but never gave a name; investigators have never established whether she gave birth or what became of her child.

Nearly 30 years later, Celina has never been found. Willingboro Police and the National Center for Missing & Exploited Children still treat it as an open endangered-missing-person investigation, and authorities have said they remain hopeful that both Celina and her child could be alive.

For more than 200 years, treasure hunters have dug into a small island off Nova Scotia, chasing a story about a mysterious shaft called the Money Pit. Legend says that in 1795, a teenager noticed a strange depression in the ground and found layers of wooden platforms as he dug, before seawater repeatedly flooded every attempt to reach whatever lay below.

The theories became bigger with every failed excavation: pirate treasure, Captain Kidd’s gold, Templar relics, Shakespeare’s manuscripts, even the Ark of the Covenant. Searchers have found old wood, coconut fibre, tools, and fragments of material but never a confirmed treasure cache.

The truth may be less romantic. Some historians and geologists argue the original “Money Pit” story lacks reliable contemporary documentation and that the feature may have been a natural sinkhole, with later digging creating much of the mystery itself.

So Oak Island remains unsolved, not because anyone has proved a spectacular treasure exists, but because nobody has proved exactly what early visitors did there, or why the legend has survived for more than two centuries.

Between 1976 and 1986, three young Native American women were murdered, mutilated, and dismembered in Oklahoma City. Their deaths were linked by the apparent care taken to conceal, and degrade their bodies, leading investigators to believe a single unidentified offender was responsible: the Oklahoma City Butcher.

The victims were 18-year-old Cathy Lyn Shakelford, found in an abandoned house in 1976; 22-year-old Arley Bell Killian, whose remains were discovered across a neighbourhood in 1979; and 22-year-old Tina Marcia Sanders, found in an alley in 1986. All were vulnerable, unhoused Native women, a fact that shaped both their risk and the limited attention their disappearances initially received.

Serial killer Henry Lee Lucas once claimed responsibility for Killian’s death, but his confession was not considered reliable; he repeatedly confessed to crimes he did not commit. Other possible suspects have been discussed over the years, but no one has been charged and the identity of the Oklahoma City Butcher remains unknown.

Today, the murders remain open cold cases, and Oklahoma City Police continue to seek information. The story is not only about an unknown killer, it is about three women whose names must not be eclipsed by the name given to the person who killed them.

In 1968, a man searching for a well site in rural Kentucky found the body of a young woman wrapped in canvas. She had been strangled and left without identification; for three decades, the grave marker simply read “Tent Girl.”

Then amateur researcher Todd Matthews, whose future father-in-law had found her body, became determined to learn her name. In 1997, he created one of the early true-crime identification websites, TentGirl.com, and searched emerging online missing-person databases and classified listings.

In 1998, Matthews found a post from Rosemary Westbrook, an Arkansas woman looking for her missing sister, Barbara Ann Hackmann Taylor. The age, location, timeline, and family photographs matched. Authorities exhumed the body, and DNA confirmed that Tent Girl was Barbara, who had been 24 when she died.

It became a landmark moment in online sleuthing: the internet did not solve the murder, but it helped return a name to a woman who had been anonymous for 30 years. Barbara’s killing remains officially unsolved.

In 1985, a hunter found a 55-gallon barrel in the woods near Bear Brook State Park in New Hampshire. Inside were the bodies of a woman and a little girl. Fifteen years later, police found a second barrel nearby containing two more children. For decades, none of the four victims had names.

DNA eventually exposed the man investigators believe was responsible: Terry Peder Rasmussen, a serial offender who lived under numerous false identities, including “Bob Evans.” Dubbed the “Chameleon Killer,” he moved across the United States, leaving behind fractured families, missing women, and children whose identities he tried to erase.

In 2019, genetic genealogy identified the woman as Marlyse Honeychurch and two children as her daughters, Marie Vaughn and Sarah McWaters. The final child, once known only as “the middle child,” was identified in 2025 as Rea Rasmussen, Rasmussen’s own daughter.

Rasmussen died in prison in 2010 while serving time for another murder, so he was never tried for the Bear Brook killings. All four victims now have their names back, but the disappearance of Rea’s mother, Pepper Reed, remains an active mystery.

In March 1997, deputies entered a rented mansion in Rancho Santa Fe, California, and found 39 members of Heaven’s Gate dead by suicide. They were dressed alike in black clothing and Nike trainers, lying in neatly prepared beds, one of the most unsettling mass deaths in modern U.S. history.

The group, led by Marshall Applewhite, believed human bodies were temporary “containers.” As Comet Hale, Bopp passed Earth, Applewhite convinced followers that an alien spacecraft hidden behind it would carry them to a higher existence, if they abandoned their bodies first.

Over several days, the members took phenobarbital mixed with applesauce or pudding, drank vodka, and used plastic bags to ensure death. The victims, 21 women and 18 men, aged 26 to 72, included Applewhite himself. Authorities found no evidence that they had been physically forced, but the case remains a devastating example of how coercive belief and isolation can lead ordinary people toward an extraordinary tragedy.

In 1974, 28-year-old Karen Silkwood worked at Kerr-McGee’s plutonium fuel plant in Oklahoma. A union activist, she raised alarms about safety failures, radioactive contamination, and alleged falsification of quality-control records, then testified to the Atomic Energy Commission about the risks facing workers.

On November 13, she was driving to meet a New York Times reporter and a union official, reportedly carrying documents she believed could expose the company’s practices. She never arrived. Her car left Highway 74 near Crescent, Oklahoma, struck a concrete structure, and Silkwood was killed; the folder of documents she was said to be carrying was never found.

Investigators officially ruled it a single-car accident, concluding she may have fallen asleep at the wheel after taking prescription medication. But disputed physical evidence, the missing papers, and her prior plutonium contamination left enduring suspicions of foul play, suspicions that have never been proven. Her family later settled a lawsuit against Kerr-McGee for $1.38 million, with the company admitting no liability.

In March 2002, John Darwin paddled his canoe into the North Sea off Seaton Carew and disappeared. Searchers found wreckage, his family mourned, and his wife Anne claimed more than £500,000 in insurance and related payments. But Darwin had not drowned: he was alive, hiding in a bedsit next door to the family home while his two sons believed their father was dead.

Five years later, he walked into a London police station claiming he had amnesia. The story collapsed when investigators found a photograph of John and Anne together in Panama, taken while they were planning a new life abroad.

In 2008, both were convicted of fraud. John received six years and three months in prison, Anne six and a half years, after a deception that did not just target insurers, but shattered their own family.

In 1928, May Donoghue was drinking ginger beer at a café in Paisley when a friend poured the last of an opaque bottle into her glass. Out came the decomposed remains of a snail, something she could not have seen before drinking from it. She later became ill and sued the drink’s manufacturer, David Stevenson.

The problem was that May had not bought the drink herself, so she had no contract with the manufacturer. But in 1932, the House of Lords ruled that a maker of products owes consumers a duty to take reasonable care, even without a direct contract.

That decision, Donoghue v Stevenson, created the modern “duty of care” principle at the heart of negligence law. One alleged snail in one bottle of ginger beer changed consumer protection and personal-injury law around the world, although whether the snail was ever actually there was never proved in court.