Celebrants gather at Stonehenge on June 20 to watch the sunset on the eve of the summer solstice.
The June solstice marks the longest day of the year in the Northern Hemisphere and the shortest day of the year in the Southern Hemisphere. It has long been an important religious, cultural, and agricultural marker for people around the world. (Related: "Summer Solstice 2013: Why It's the First Day of Summer.")
—Jane J. Lee