Out-of-place artifact

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.

The term "out-of-place artifact" is rarely used by historians or scientists. Its use is largely confined to cryptozoologists, proponents of ancient astronaut theories, Young Earth creationists, and paranormal enthusiasts. The term is used to describe a wide variety of objects, from anomalies studied by mainstream science and pseudoarchaeology far outside the mainstream to objects that have been shown to be hoaxes or to have mundane explanations.

Critics argue that most purported OOPArts which are not hoaxes are the result of mistaken interpretation, wishful thinking, or a mistaken belief that a particular culture couldn't have created an artifact or technology due to a lack of knowledge or materials. Supporters regard OOPArts as evidence that mainstream science is overlooking huge areas of knowledge, either willfully or through ignorance.