The "Black Hole of Calcutta" was a tiny prison cell in Fort William, in the Indian city of Calcutta. According to John Zephaniah Holwell of the British East India Company, on June 20, 1756, the Nawab of Bengal imprisoned 146 British captives inside the airless room overnight - when the chamber was opened the next morning, only 23 men (including Holwell) were still alive.
This story inflamed public opinion in Great Britain, and led to the characterization of the Nawab, Siraj-ud-daulah, and by extension all Indians as cruel savages. However, there is much controversy surrounding this story - though the prison was very much a real location that was later used by British troops as a storage warehouse.
Controversy and Truths
As a matter of fact, no contemporary sources ever corroborated Holwell's story - and Holwell has since been caught fabricating other incidents of similar controversial natures. Many historians question the accuracy, positing that perhaps his account may have been a mere exaggeration or entirely a figment of his imagination.
Some posit that given the dimensions of the room at 24 feet by 18 feet, it would not have been possible to cram more than about 65 prisoners into the space. Others say that if several had died, all of them inevitably would have at the same time as limited oxygen would have killed everyone simultaneously, not depriving them individually, unless Howell and his surviving crew had strangled the others to save air.
The story of the "Black Hole of Calcutta" actually could be one of history's great scams, along with the "bombing" of the battleship Maine in Havana Harbor, the Gulf of Tonkin Incident, and Saddam Hussein's putative weapons of mass destruction.
Consequences and the Fall of Calcutta
Whatever the truth of the case, the young Nawab was killed the next year at the Battle of Plassey, and the British East India Company assumed control over most of the Indian subcontinent, ending the utilization of the "Black Hole of Calcutta" as a place for prisoners of war.
After the British conquered Nawab, they established the prison as a warehouse for stores during the preceding wars. In memory of some 70-odd troops that had supposedly died in 1756, an obelisk was erected in a graveyard in Kolkata, India. On it, the names of those that Howell wrote had died so he could live are immortalized in stone.
A fun, if little-known fact: the Black Hole of Calcutta may have served as the inspiration for the name of the same astrological regions of space, at least according to NASA astrophysicist Hong-Yee Chiu. Thomas Pynchon even mentions the hellish place in his book "Mason & Dixon." No matter how you regard this mysterious ancient prison, it has inspired folklore and artist alike since its closure.