Thousands of people gathered before dawn at the UK's Stonehenge to mark the sunrise on the first day of summer in the Northern Hemisphere on Wednesday. Around 9,500 attended the event in the 4,500-year-old stone circle, with another 600 at the nearby Avery site, which is also a Neolithic monument.

Modern-day druids celebrated the summer solstice in the wake of the old Celtic priests, with other non-Christian worshipers performing rituals. Visitors also sang, beat drums or practiced yoga.

Researchers still debate the exact purpose of the 30-meter ceremonial site in Southern England. However, the 25-ton stone elements are aligned with the movements of the sun in the sky, suggesting that one of its uses was to serve as a calendar.

English Heritage, the organization in charge of the care of historic sites in England, tweeted a time-lapse of the sunrise.

Read more: A brief history of humanity's fascination with the summer solstice

UK authorities usually restrict access to the iconic monument, but visitors are allowed during summer and winter solstices and other big events.

dj/rc (dpa, AP, Reuters)