One of the unsolved mysterious that can't be explain by sciences is Out-of-place artifact (OOPArt).
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.
An out-of-place artefact is an object that exists in a place in which it is impossible for it to exist. OOPArts are often of interest to creationists and others who seek evidence that may refute the theory of evolution; they are also used to support religious descriptions of pre-history, ancient astronaut theories, or the notion of vanished civilizations that possessed knowledge or technology more advanced than our own.
Here are few famous OOPArt:
1. Dendera Light
2. Antikythera Mechanism
3. Baghdad Battery
4. Crystal Skull
5. Nazca Lines
The Nazca Lines a series of geoglyphs located in the Nazca Desert, a high arid plateau that stretches 53 miles or more than 80 kilometers between the towns of Nazca and Palpa on the Pampas de Jumana in Peru. They were created by the Nazca culture between 200 BC and 700 AD. There are hundreds of individual figures, ranging in complexity from simple lines to stylized hummingbirds, spiders, monkeys, and lizards. The Nazca lines cannot be recognized as coherent figures except from the air. Since it is presumed the Nazca people could never have seen their work from this vantage point, there has been much speculation on the builders' abilities and motivations.