It is of course impossible to ever know for sure how the stones were brought to Stonehenge from the site, about 20 miles away, where they were quarried. However, archaeologists have tried to recreate ways in which it might have been done. The most commonly believed theory is that the blocks were pulled to the site using either rollers or primitive tracks. The stones might have been pulled over log rollers that would be constantly placed in their path. Or they might have been put on sleds and pulled over greased rails. They had to have come by land in a time when the wheel was unknown in Britain. Because of this, the idea of the rollers or the tracks is the most commonly held idea.