As it turns out, American Horror Story's Bette and Dot Tattler aren't by any means the only twins out there with an incredible story to be told - but when it comes to dark and troubling tales, there aren't too many out there that can match that of June and Jennifer Gibbons, the Silent Twins.
It's a story that begins with a troubled childhood, and after years of fear, hatred, imprisonment and un-explained death, might just have a happy ending.
Before that, though, there's a whole lot of strange, tragic history to tell...
Meet the Silent Twins of Haverfordwest...
June and Jennifer Gibbons were born in Barbados on the 11th April, 1963, and, shortly after, moved with their family to a small town in Wales named Haverfordwest.
There, though, the twins found themselves living in a challenging, often very antagonistic world - one in which they were the only non-Caucasian children in their community, and were treated poorly as a result.
Soon, the pair found themselves living in their own private world - only communicating with one another, and even then exclusively in a language of their own invention.
Over the years, their attachment grew stronger, to the point that they were sent to separate boarding schools to attempt to bring them out of their self-created isolation. Both soon became catatonic, though, and were soon reunited.
The Story Takes a Dark Turn
At the age of 16, the twins took up writing - but a lack of success with a series of often-disturbing horror, crime and romance tales soon led to real-life crime.
At the age of 18, the two embarked on a crime spree, and after a spell of petty theft and arson, they were arrested and sent to the notorious English mental-health hospital, Broadmoor.
And there they remained for the next 11 years, still as close as ever, though split up into different wards. The time was a troubled one, though, with the twins alternately remaining as close and insular as ever for much of the time, but periodically attacking one another.
Eventually, though, the pair were set to be transferred to a less-severe hospital in Wales - but before they ever arrived there, one of them was set to meet her end.
The Lone Silent Twin
Before arriving at their new home, the twins had decided that, as Marjorie Wallace, who knew them personally, puts it:
"One of them would have to die in order to set the other free. The question was, who would make the sacrifice - or should both?"
Indeed, before leaving Broadmoor, Jennifer turned to Wallace and told her:
"Marjorie, I'm going to die. We've decided."
And, so, when the day of their release from Broadmoor finally arrived, the twins stepped out of their home of 11 years - and within ten minutes, Jennifer slumped onto her sister's shoulder.
She dies at 6.15pm that same evening.
The Mystery That Lingers
The strangest thing, though? Jennifer died of sudden acute myocarditis - an inflammation of the heart muscle - and yet no evidence as to why, or for why it could have happened at the exact moment the twins seemed to predict it would, has ever been found.
Indeed, at the inquest into Jennifer's death, as Wallace puts it:
"...the pathology report mentioned a host of possible causes, from viral infection to drugs, poisons or sudden exercise, but there was no evidence of any one of these. The mystery of her death remains unsolved."
There is, though...
Some Kind of Happy Ending
June, left alone by her sister's sudden death, was distraught - but also strangely freed by what she called "a sweet release."
As she later put it:
"We were war-weary...It had been a long battle - someone had to break the vicious circle."
And, finally, Jennifer,it seemed, had.
Soon, June found herself living a quiet, seemingly happy life, re-united with her parents and younger sister in Wales.
Alone,but free. And no longer silent.