Stonehenge, as you already know, stands as a group of upright stones on Salisbury Plain, Wiltshire, England. Their axis stands roughly pointing to the sunrise at the winter and summer solstices. Some scientists believe that the people also used it to foretell eclipses of the sun and moon.
The site may have an observatory where the people performed rituals. An early belief that it was a temple was never really proven. There is another theory that the Druids had something to do with this structure. But the Druids didn't appear in Britain until a few centuries before the Christian era. So that belief is not backed up by science.