A GIANT fort-like structure has just revealed itself in deepest Antarctica, sparking claims of an ancient civilisation once roaming the polar region. What apperars to be the remains oval shaped "building" is 400ft across and appears to have all the hallmarks of being a sizeable, man-made construction - similar to a mediaeval motte and bailey castle. If true, it would reshape everything scientists thought they knew about humanity's past as it would prove people inhabited what was previously thought to be a desolate region. Satellite imagery clearly shows the structure, which closely resembles the ruins of a once giant building. It is so symmetrical it has raised questions as to whether nature alone could have designed it. Scientists initially thought the discovery could be a sastrugi – a natural phenomenon formed by years of being battered by strong, freezing winds and heavy snowfall. But sastrugies always form a distinctive shape based on the direction of the wind and rarely appear as