Organizers and participants call it everything from 'a planetary Woodstock' to 'the dawn of a new age,' while skeptics dismiss it as summer madness and a waste of time.
For a variety of reasons, however, thousands -- perhaps millions - of people worldwide were prepared to greet the dawn Sunday by taking part in an event called Harmonic Convergence.
'Everyone has a different view of what Harmonic Convergence is,' Tami Simon of Boulder, Colo., spokeswoman for a nationwide HC (Harmonic Convergence) radio network, said.
New Age scholars led by author Jose Arguelles recently determined that Aug. 16, 1987, was a crucial date for planet Earth and its occupants.
Arguelles said the Mayan, Aztec and Hopi Indian calendars predicted Sunday would mark the beginning of the final quarter century in a 5,000-year cycle, or the end of the Old Age. He also cited a unique but disputed alignment of heavenly bodies and the movement of a 'galactic beam.'
The teachings he cited said the next 25 years would be a 'purification period' climaxing in a great transformation as the New Age begins in 2012.
The weekend, he wrote, marked a 'confluence of astronomical and chronological phenomena that made it 'a turning point of historic magnitude exceeding anything we've ever known.'
To insure a smooth transition into the New Age, he said, at least 144,000 people had to take part in the Harmonic Convergence. Meeting that quota should be no problem.
Many, however, dismiss any cosmic significance in the event.
'I think this is typical summer madness,' James Cornell of the Harvard-Smithsonian Center for Astrophysics said. 'There is no scientific basis for any claims of supernatural or superphenomenal activities on Sunday, Aug. 16.'
He dismissed the event as 'one of those weird ideas that doesn't really have anything to do with what we understand about the galaxy.'
Undaunted, large numbers of people said they would celebrate, individually or at mass gatherings.
Large crowds were expected at what the organizing group Global Family of Boulder, Colo., called 'power points,' sort of planetary accupuncture points.
Those points include New Mexico's Chaco Canyon and Mt. Shasta in Northern California, where crowds of up to 20,000 were expected to resonate in harmony with the planet.
'We've been getting 50 calls or more a day for the last two weeks for information about the event,' Daphne Sanderson of the Chaco Canyon group said. 'But it's the thousands just planning on coming that we don't know about.'
Other 'power points' include Harney Peak in the Black Hills of South Dakota; Serpent Mound, Ohio; Haleakala, Hawaii; Sedona, Ariz.; Niagara Falls and the Grand Canyon.
Overseas, celebrations were scheduled at hundreds of locations, including sacred sites at Machu Picchu, Peru; the Pyramids of Egypt; Mt. Olympus in Greece; Mt. Fuji in Japan and the banks of the Ganges River in India.
Actress-author Shirley MacLaine, who popularized 'channeling' and other forms of spiritual awareness, was in the Soviet Union to participate in Harmonic Convergence events at Lake Baikal.
Sedona, Ariz., officials expected more than 5,000 people to converge on the town of 8,000. Hotels as far away as Flagstaff, about 30 miles north, were filled up by Friday.
In Hawaii, at least 1,000 people were headed for Haleakala National Park on the island of Maui. A delegation from Finland planned on opening relics from a 1,000-year-old tomb.
Parking was the problem facing officials at Serpent Mound, an Adena Indian ceremonial site. 'If 4,500 people show up, there's going to be a major parking problem,' said spokesman Jim Cannon.
Organizer Gordon Franklin predicted a Serpent Mound crowd of 12,000.
'We've been getting phone calls from New Jersey, Maine and Pennsylvania, and one source called today to say there would be at least 1,000 people coming down just from Cleveland,' he said.
Overcrowding could pose a problem at environmentally fragile areas like Haleakala and Mt. Shasta and Mt. Rainier in Washington state.
Forest Service spokesman Ron Ottrin said 500 people had arrived by Saturday at Mt. Shasta, but that as many as 5,000 could be at the base of the snow-capped peak in time for the event.
Many celebrants took the advice of Global Family's Jeff Daly, who said trips to power points were not necessary.
'All you have to do is sit on Mother Earth somewhere and open your heart.'
Jane Combelic of Phoenix was one who planned on doing just that.
'A lot of individuals are doing their own thing,' Combelic said. 'I'm just going camping by myself. Just like a spiritual retreat.'
'The Harmonic Convergence is a grass-roots movement. It's been a totally word of mouth thing. It really makes me believe it's totally guided from some other plane.'