Revelers were banned from holding solstice ceremonies at the 5,000-year-old Stonehenge site in 1985 after clashes with police, and a four-mile exclusion order was later put in place following a series of disorder problems.
The stones are the remnants of the last in a sequence of circular monuments aligned along the rising of the sun at the midsummer solstice - the longest day of the year.
There has always been intense debate over exactly what purpose Stonehenge served and how it came to be built. Some experts believe it is aligned with the sun simply because its builders came from a sun-worshipping culture, while others believe the site was part of a huge astronomical calendar.Others theorize that Stonehenge was a druid temple.
In 1998, English Heritage, which owns the site, allowed 100 people to gather within the encircling rocks at dawn to celebrate the summer solstice as part of a step toward admitting larger crowds.
Last year, Stonehenge was opened to 150 druids who planned a ceremony there to see the sun rise on the year's longest day. But about two hundred people gatecrashed the event and clashed with police after pushing through the perimeter fence surrounding the stones and occupying the site. Sixteen people were arrested, and others remained there in defiance of police, prompting the cancellation of the druid celebration.
English Heritage said it is expecting several thousand people to visit the site overnight, but the organization said it was confident the night will pass without any problems. Security guards and stewards will be at the site, with backup from the police, but English Heritage says the emphasis will be on the public's enjoyment of the event.
"We've made arrangements to try to make this a happy and peaceful solstice for people," said an English Heritage spokeswoman, speaking on customary condition of anonymity.