Clad in antlers, black cloaks and oak leaves, a group of druids gathered at the Heel stone - a twisted, pockmarked pillar at the edge of the prehistoric monument - to welcome the rising sun as revelers danced and whooped.
"Happy Solstice!" said Laura Tungate, a 26-year-old financial adviser from Newcastle, who wore a giant rainbow sweater and offered hugs to smiling passers-by.
Taking a swig from a mug of vodka and Red Bull, she said she had been coming to the Solstice ceremony for the past eight years.
"I love the whole vibe, and the energy, and the fact that these stones, that they are alive, they do breathe, and they do grow ... and they're massive!" she said.
About 24,000 people gathered at the stone circle in Wiltshire, in southwestern England. Dancers writhed to the sound of drums and whistles as floodlights colored the ancient pillars shades of pink and purple. Couples snuggled under plastic sheets.
Solstice celebrations were a highlight of the pre-Christian calendar and in many countries bonfires, maypole dances, and courtship rituals linger on as holdovers from Europe's pagan past.
In more recent years, New Age groups and others have turned to Stonehenge to celebrate the solstice, and the World Heritage Site has become a magnet for men and women seeking a spiritual experience - or just wanting to have a good time.
Jeanette Montesano, a 23-year-old recently graduated religion student from New York City and a self-described pagan, said she had been saving for a year to make it to Stonehenge, comparing the importance of the trip to the Muslim pilgrimage to Mecca, in Saudi Arabia.
"It's not the hajj, but it is (thousands of) people in a little circle. I wanted to experience something like that," she said.
But the celebrations can also attract their share of troublemakers - police closed the site in 1984 after repeated clashes with revelers. English Heritage, the monument's caretaker, began allowing full access to the Stonehenge again in 2000.
Police and about 200 English Heritage stewards were deployed to cast a watchful eye on the stones, and to keep the hedonists from getting out of hand. Police reported four arrests for public order violations.
"It's a little bit silly but it's been very enjoyable. It's not threatening at all."
Solstice celebrations also take place in other countries, though most are deferred until the last weekend in June. Swedes will gather to sip spiced schnapps, Danes will light bonfires, and Balts and Finns will flock to the countryside to dance, sing, and make merry under the midnight sun in one of the region's most important holidays.
The southern hemisphere, meanwhile, was caught in the depths of winter. In Antarctica, where permanent night rules from mid-April through August 20, staff at New Zealand's Scott Base science facility celebrated the midwinter solstice with a formal dinner of speeches and toasts.
Scott Base Manager Glenn Powell said it was a special time for him and his colleagues.
"We do survive in total darkness - so the return of the sun (from the most distant point it reaches on June 21) is a very special occasion," he told The Associated Press by phone. "We're celebrating the fact that it won't go any further away."
Stonehenge, on the Salisbury Plain 80 miles (130 kilometers) southwest of London, was built between 3,000 B.C. and 1,600 B.C. It is one of 20 monuments competing to be named one of the new seven wonders of the world in a massive online poll, but its original purpose is a mystery.
Some experts say the monument's builders aligned the stones with the sun as part of their sun-worshipping culture, although exactly how and why the monument was built remains shrouded in the mists of time.