A solstice is a time of the year when Earth is pointed either the closest toward the Sun or the farthest away from it. On the summer solstice, there are more minutes of daylight than there are on any other day of the year; on the winter solstice, there are fewer minutes of daylight than there are on any other day of the year. In the northern hemisphere, the summer solstice occurs around June 21 of each year, when the North Pole is pointed closest toward the Sun, and the winter solstice occurs around December 21 of each year, when the North Pole is pointed farthest away from the Sun.
Archeologists generally agree that ancient Stonehenge near Wiltshire, England, was used long ago to mark solstices and equinoxes.