The Coso Artifact
February 13, 1961 - It was on this day that three rockhounds came across what seemed to be an anachronism. They found what appeared to be a manmade piece of machinery and circuitry encased in a 500,000 year old rock.
Wallace Lane, Virginia Maxey, and Mike Mikesell were searching for geodes in the desert near Olancha, California. They found something that looked like most of the other stones they were gathering, but when Mikesell tried to cut the rock open, he ended up destroying the diamond bit blade on his saw. Instead of a crystal-lined cavity, what was revealed inside the rock was an piece of metal machinery.
It quickly became a huge story and was eagerly promoted by UFO and time travel enthusiasts as proof of some other-worldly activity. But as if often the case, the reality behind the artifact was very mundane. Investigators identified the mysterious piece of technology as a Champion sparkplug from the 1920s. It was a common component of Model T and Model A engines.
Other tests showed that the sparkplug could've become encased in an iron oxide concretion after many years of weathering in the desert. So despite reports that a sparkplug from Atlantis had been discovered, this mystery ended without even a spark.