That which we know the least about is often the most interesting. A case in point is the civilization of the Olmecs. This flourished in Mexico between 1500 B.C and 400 B.C., leaving behind much intriguing evidence in its art and archaeological remains but no written record to explain anything. Because of this, the Olmec have become a fertile source of historical riddles, mysteries, and speculation. This lost world is the subject of "Olmeca: the Most Ancient Civilization of the Americas," a medium-size exhibition at the slightly out-of-the-way Ancient Orient Museum.

Located on one floor of a building in the Sunshine 60 complex in Tokyo's Ikebukuro area, the museum's space has very little of the mystique and glamour of the ancient times to which it is dedicated. But, for this exhibition, it has made some attempt to recreate the atmosphere of the Olmec world. At the entrance, visitors are greeted by a full-size replica of one of the giant stone heads for which the Olmecs are famous, flanked by a bit of tropical shrubbery and a stuffed jaguar.

The distinct features of these stone heads have prompted imaginative speculation in some quarters that the Olmecs may have been immigrants from Sub-Saharan Africa. This, though, is the same sort of overambitious, blue-sky thinking that attributes the pyramids in the New World to architects from the Old. More down-to-earth theories point to artistic stylization and technical reasons, such as stone-carving techniques, as the reason behind the characteristic look of these statues.