A statuette which Greek archaeologists are calling a "7,000-year-old enigma" has gone on show in the National Archaeological Museum in Athens.
The bird-like object was carved from granite - without the benefit of metal tools, as it dates from the Final Neolithic period.
The 36cm (14in) statuette has a pointed nose, round belly and cylindrical legs.
But it has mystified archaeologists, who do not know exactly what it is or where it came from.
The museum says the figure is asexual, with no sign of breasts or genitals.
But it says it is difficult to say whether that is a result of the challenge of carving granite without metal tools, or whether it was deliberate and could tell us something about the place of gender in Neolithic society.
The piece is on display until 26 March as part of the Unseen Museum display, a temporary exhibition of some 200,000 antiquities held in the museum vaults and not on permanent show.