[GH85Carrera]

A "petrified" ladder in Baume-les-Messieurs, France
The ladder most likely underwent the process of calcification. Being laid on the limestone surroundings known to contain calcium carbonate, when the rainwater poured over, it dissolved the carbonate compounds contained in limestone and subsequently soaked the surface of the ladder in calcium and magnesium ions.
Over time, the minerals solidified on ladder's surface. Researchers estimate the ladder is roughly 150 years old










The Porsche 917 sports prototype racing car's air-cooled flat-twelve engine was introduced in 1969. The engine was based on the 917's previous flat-eight engine, but with a V12 crankshaft configuration instead of a boxer configuration. The engine's unique design, which Porsche called the "180° V12", helped keep the engine compact. The engine's opposite pistons would reach top-dead and bottom-dead center at the same time, and the crankshaft had two rods that shared the engine's six journals. This design also reduced the number of bearings that needed lubrication, which lowered friction and allowed for a shorter and lighter crankshaft.