It was 1986, when the goo appeared.
At first, it was just a 50-metre long smudge outside Caracas, but it soon grew to conquer the roads of Venezuela’s capital.
An inch-thick greasy black blob as ‘slick as ice’, to this day no one knows what it was, or where it came from, just that it killed hundreds of people.
Was it political sabotage? Aliens?
This is the story of La Mancha Negra, or the Black Stain.
First spotted by workers as they patched up 30-year-old asphalt between the city and its airport, over two decades the patch of mysterious slime soon grew to cover eight miles of roads. In the five years up to 1992, it reportedly claimed the lives of 1,800 drivers and passengers whose cars spun out of control on the giant slick.
Yet despite this apparent death toll – never officially confirmed – there is much more we don’t know about the black goo than we do.
It seemed to be alive. La Mancha Negra contracted and expanded with the weather, growing when it was hot and wet but shrinking when it was cold and dry.
Although it claimed miles of the road, it also lurked in tunnels and, incredibly, the uphill slopes outside the airport.
Some who saw it described it as ‘gummy’. Others avoided it at all costs.
‘They can offer me double the fare, but if La Mancha Negra is bad I won’t drive,’ said taxi driver Orlando Acevedo. ‘It’s not worth dying for.’
Another claimed to face the blob ‘frequently’.
‘Driving with La Mancha Negra is like driving in a grand prix,’ he said. ‘You got to be careful, or you’ll die.’
Despite the Venezuelan government throwing what they say was ‘millions of dollars’ at the problem, the mysterious glob was nothing if not persistent.
In 1994, eight years after its first appearance, and with its death toll rising higher and higher, the Ministry of Transport and Communications attempted to wash away La Mancha Negra, working under the assumption it was a paste of oil and dust.
It didn’t work.
They upped their game with pressure washers. When that didn’t work, they tried scrubbing it away with detergents, and repeatedly scraped away the top layer of the roads – but the alien substance still appeared.
When the government poured tonnes of pulverised limestone over the stain to ‘dry it up’, residents complained the roads were too dusty, and the air was unbreathable.
But it worked. For a while.
Ten years later in 1996, La Mancha Negra appeared again.
The government consulted experts in the US, Canada and Europe. Equipment was brought in from Germany which seemed to scar away the substance – until it reappeared again in 2001.
Two decades on from its last appearance, we are no closer to understanding what la Mancha Negra was, or is.
Conspiracy theories are rife, as people ponder if it was just oil oozing from the asphalt, or oil from overworked car engines. A fungus. Maybe an alien fungus.
‘This is a really old story and there are lots of myths and realities about this,’ said engineering professor Dr Ramanan Krishnamoorti, speaking to Popular Mechanics. ‘The size and scope and timing of the “oozing” and then the repetition after five years made for a real mystery.’
For now, it seems as if the blob is dormant, and with little reporting from the time,evidence to help unravel the mystery is scarce.
Will it return? We don’t know.
If it does, in the age of smartphones and social media, you can bet it won’t just be the taxi drivers of Caracas taxi drivers staring into the abyss of the big black goo.