By the end of the late Stone Age, people built megalithic structures such as Stonehenge. The position of the pillars indicates that the primitive builders understood astronomical basics such as the summer solstice. The date of construction of Stonehenge remains in question. . It is widely believed that construction began some years ago and was worked on in three phases over a long period of time. In any case, the stones came from a quarry miles away, which is a mystery in itself, for no one knows for sure how these primitive people moved the massive stones without the aid of mechanical devices. The exact purpose of Stonehenge remains a topic of debate.