Stonehenge（巨石阵）is a strange circle of very big stones in southern England．
It was built over a period of a thousand years，probably between 3000and 2000BC．Some of the stones weigh over 25 tons！As you can tell from this picture，these big stones were clearly arranged with some purpose（目的）in mind．But what was it？
Most historians aGREe that it was built as a temple，but it was also probably used as an early astronomical（天文学的） tool！For example，on the Summer Solstice（夏至，the longest day of the year），the rays（光线）of the sun shine perfectly in the center of the structure．Interesting，huh？
