As many as 21,000 druids, spiritualists and revelers gathered at Stonehenge Tuesday to celebrate the longest day of the year: the summer solstice.

As the sun rose at approximately 4:58 a.m. GMT (11:48 p.m. ET), many cheered, beating drums and playing pipes.

The solstice is a rare occasion during which visitors are allowed to walk among the stones and touch them.

Scholars say the site was erected between 3000 BC and 1600 BC. It was not known whether it was a temple, burial ground, or astronomy site.

Druids are drawn to Stonehenge, believing it was a center of spiritualism over 2,000 years ago.