At sunrise on the Northern Hemisphere’s longest day of the year — the summer solstice– thousands of modern-day druids, pagans and partiers gather in the countryside near Salisbury, England, to cheer as the first rays of light stream over a circular arrangement of stones called Stonehenge. The original purpose of the ancient monument remains a source of academic debate. The large stones erected about 4,000 years ago are aligned with the summer solstice sunrise, leading scholars to suggest a link to an ancient sun-worshipping culture. Click the “Next” arrow above to learn about seven more ways ancient cultures marked the solstices– the longest and shortest days of the year.