By the 5th millennium BC these peoples had fashioned one of the world 's earliest known astronomical device ( roughly contemporary to the Goseck circle in Germany ) , about 1000 years older than but comparable to Stonehenge ( see sketch at right ) . By the 5th millennium BC these peoples had fashioned one of the world 's earliest known archeoastronomical devices ( roughly contemporary to the Goseck circle in Germany and the Mnajdra megalithic temple complex in Malta ) .