Good luck, old cock, sorry to leave it in such a mess.

— Note left by the outgoing Chancellor, Reginald Maudling, to his successor, Jim Callaghan, after the 1964 general election

Collegial joke.

La Mancha Negra (The Black Stain) is a mysterious black substance that has oozed from roads in Caracas, Venezuela, first appearing in 1986.


In 1986, La Mancha Negra first appeared as a 50m long smudge. It was noticed by workers as they patched the 30-year-old asphalt on a highway between Caracas and its airport.

Gummy in texture, the blob rendered the roadway extraordinarily unsafe, causing vehicles to crash into one another or run off the road.

described as an inch-thick, greasy, black blob that has the consistency of chewed bubble gum, though Venezuelans describe the roads it covers as “slick as ice”.

As much as 13 km of highway were soon covered with the unknown material that contracted and expanded with the weather. It was found to grow when conditions were hot and wet but shrink when it was cold and dry. It seemed to prefer tunnels and the uphill slopes outside the airport.

In January 1996, the roads became slick with the substance once more, due to the lack of maintenance, low rainfall and the poor condition of vehicles in Caracas. Special cleaning equipment was brought in from Germany, and the phenomenon seemed to have abated for a few years. However, La Mancha Negra reappeared in 2001 on several roads in Caracas, including Baralt, Nueva Granada, Fuerzas Armadas, Sucre, and Urdaneta Avenues.


A team of the Venezuelan Ministry of Transport and Communications believed La Mancha Negra was composed of dust, oil, and various organic and synthetic materials.

one report showed it “was a mixture of used engine oil and highly corrosive brake fluid”

some believed that raw sewage from nearby slums was running downhill, under the asphalt, and causing a chemical reaction that broke the roads down.

oil that seeped from sub-standard asphalt, with Venezuelans believing someone laid flawed asphalt that would leak oil when temperatures rose

The most accepted theory is that La Mancha Negra is the result of countless leaky, old cars spraying their fluids over the roadway. Professor Giannetto, a commissioner of the Ministry of Transport and Communications, believed that La Mancha Negra was an accumulation of dust and oil released from cars that formed a paste on the roads. […] Venezuelans would drive dated gas guzzlers, stating ‘Locals call the highway “la mancha negra,” or the black stain, because it literally shines with the oil drippings of thousands of big cars that labor up an incline into the city each day.’ Water-tank trucks periodically spray down the road in vain attempts to wash away some of the oil slick that causes hundreds of accidents a year”.

Both “gummy in texture” and “slick as ice”. Both “oozed from roads” and “spraying their fluids”. Could there be two phenomena with the same name here? Oil slicks from cars, and the weird gummy stuff? Or the same stuff, at different stages of its life cycle? (Add dust and tyre particles to oil, get something with the texture of pitch).

Originally discovered on Adel Souto’s site.

Paul Cauthen Closest thing there is to a reincarnation of Johnny Cash,. bonus