Though widely disputed, legend holds that the mysterious Stonehenge structure was constructed for the summer solstice and used to represent a calendar system. During sunrise on the summer solstice, sun rays hit a particular point on the horizon, which could have served as a starting point for counting the days. To this day, thousands of revelers still gather at the stones to celebrate the solstice.
Stonehenge isn’t the only site that holds start-of-summer festivities. Similar celebrations happen around the globe to mark the longest day of the year—often with bonfires, special drinks and dancing.