Since it has been discovered that Stonehenge was developed during the Stone Age without the wheel and other necessary developments, the hours it took for this construction is estimated in the near 40 millions of man-hours. Based on this calculated theory, it is believed that Stonehenge was created within one thousand to fifteen hundred years of construction.
These stones were not found in the immediate area, and the closest rocks similar to those in Stonehenge were found nearly two hundred miles away from Stonehenge in what is today known as Wales. Theories suggest that Stonehenge was built possibly in several stages.
Baskets
Several theories suggest how these stones were moved. The first theory suggests that baskets were weaved and created large enough to transport these stones. At this time in the Stone Age, evidence found throughout England suggests that basket weaving was, in fact, viable and a technique used. This would suggest that a few men would pick up these stones and move them onto these weaved baskets, carrying them back 200 miles until they reached the destination of Stonehenge.
All of these techniques would have been feasible in the time period and options for any other technique would be very slim to none without more modern developments.
While we can speculate on how Stonehenge was developed, there is no solid answer as to its construction. Theories can be tested and they have been, suggested a few different ways that it could have been developed without modern technology. It is safe to assume that no matter which theory is correct, the construction of Stonehenge was well before its time.