non-mainstream pseudohistorical theories relating to the formation of Olmec civilization which contradict generally accepted scholarly consensus, which holds that Olmec civilization is entirely indigenous to the region or at least to the New World.

The 16th-century portrait Mona Lisa, or La Gioconda (La Joconde), painted in oil on a poplar panel by Leonardo da Vinci, has been the subject of a considerable deal of speculation.