Druids have been marking the solstices and equinoxes at Stonehenge, near Salisbury, England, for thousands of years. In recent years, however, what had been a quiet affair has become a new-age festival, drawing thousands of people, particularly for the Summer Solstice, which is the longest day of the year in the Northern Hemisphere (because the northern half of the planet is tilted toward the sun). We start with celebrations of the Summer Solstice on Tuesday, June 21, 2011. Photo: Matt Dunham, ASSOCIATED PRESS / AP2011