An out-of-place artifact (OOPArt) is a term coined by American zoologist Ivan T. Sanderson for a historical, archaeological or palaeontological object found in a very unusual, or even impossible, location. The term covers a wide variety of objects, ranging from material studied by mainstream science, such as the Iron pillar in Delhi, to so-called ‘forbidden archaeology’ that is far outside the mainstream.
While occasional discoveries, such as the Antikythera mechanism, have forced scientists to reassess the technology of ancient civilization, most believe cases of OOPArt to be the result of mistaken interpretation or wishful thinking. Supporters regard them as evidence that mainstream science is overlooking huge areas of knowledge, either willfully or through ignorance.
The Blue Hill, Maine 11th century Norse coin found in an American Indian shell midden. Over 20,000 objects were found over a 15-year period at the Goddard site in Blue Hill. The sole OOPArt was the coin. One hypothesis is that it may have been brought to the site from a Viking settlement in Newfoundland, not by Norsemen but by seagoing Indians.
The Iron pillar in India, dating around to AD 423.
The Antikythera mechanism, a geared device manufactured ca. 100 BCE, believed to be a device for predicting the motion of the sun, moon and planets i.e. an orrery.
Tablets and artifacts discovered in Glozel, France in the 1920s and ’30s, some of which were inscribed with an unknown, undecyphered alphabet.
Read the wikipedia article here.