This truly amazing artefact is far older than mankind but was evidently made by someone. The question is: who? Discovered in the late 1990s by Zhilin Wang in a remote mountainous area in northwest China, the Lanzhou Stone is one of the most baffling out of place artefacts.
The iron pillar of Delhi.(composed of 98% pure wrought iron). Said to be from the time of Chandragupta Vikramaditya (375–413). A fence was erected around the pillar in 1997 in response to damage caused by visitors. There is a popular tradition that it was considered good luck if one could stand with one's back to the pillar and make one's hands meet behind it.
Out-of-place artifact (OOPArt) is a term coined by American naturalist and cryptozoologist Ivan T. Sanderson for an object of historical, archaeological, or paleontological interest found in a very unusual or seemingly impossible context that could challenge conventional historical chronology by being "too advanced" for the level of civilization that existed at the time, or showing "human presence" well before humans were supposed to exist.