As old as time itself!
The point at which the sun reaches its farthest point north of the equator is the Summer Solstice, well it is for the Northern Hemisphere. This occurs annually on June 20 or June 21, depending on your time zone.
Here in Southern Oregon, the moment of the Summer Solstice will be 22:04 Pacific Daylight Time (PDT) on the evening of June 20th and at 05:04 GMT/UTC on June 21 2013 in the United Kingdom.
A quick web ‘look-up’ finds that the word solstice is from the Latin solstitium, from sol (sun) and stitium (to stop), reflecting the fact that the Sun appears to stop at this time, albeit momentarily.
At the ancient stone circle of Stonehenge in Southern England, the prehistoric monument that took Neolithic builders an estimated 1,500 years to erect, for many years the Druids have celebrated the Solstice and, undoubtedly, will be doing so again.