Warnings by a US fundamentalist preacher that on Saturday is Judgment Day have sent some people into hiding or rushing to repent, while others are planning parties to wave off good Christians.
Televangelist Harold Camping's prophecy says the so-called "Rapture" will begin with powerful earthquakes at 6:00 pm local time in each of the world's regions, after which the good will be taken into heaven.
The not-so-good will suffer hell on earth until October 21, when God will pull the plug on the planet once and for all, the 89-year-old predicts.
One of the first places to be hit, according to Camping, who wrongly predicted the end of the world in 1994, would be New Zealand, but 6:00 pm came and went with no earthquakes and little local media attention.
In the United States, where Camping's evangelising organization is based, some people have been quitting their work and hitting the road to urge others to repent before it's too late.
Gregory LeCorps left his job weeks ago to take his wife and five young children on the road and warn others that the end really was nigh, the Journal News in New York wrote.
"We're in the final days," LeCorps, who said he hopes to be on a beach in South Carolina by Saturday, was quoted by the newspaper as saying.
In Australia, another early target of Camping's prediction of doom, Christians greeted news of the end of the world with scepticism and humour before the fateful hour passed without incident.
"It's not being taken seriously at all," theologian Ian Packer from the Australian Evangelical Alliance told AFP, saying the May 21 deadline was being greeted with "openly humourous talk".
"Aside from hearing about Harold Camping in the media, we would not have known about his existence," he said.
In Vietnam, thousands of ethnic Hmong converged on northwestern Dien Bien province a few weeks ago after hearing broadcasts on Camping's global religious broadcasting network that Jesus was coming on May 21.
Hundreds are believed to be hiding in forests after security forces dispersed those who were awaiting the supposed return of Jesus Christ on Saturday, a resident told AFP.
The Vietnamese government said extremists used the gathering to advocate a Hmong kingdom but the resident said he was unaware of such talk.
In Ciudad Juarez, one of the cities worst affected by Mexico's drug wars, huge billboards proclaimed that "Christ is coming back on May 21."
According to the authorities, the apocalyptic message has not provoked panic or hoarding, but one resident, Rosy Alderete, said she was "worried by the coincidence" that big earthquakes have rocked Japan and New Zealand this year.
Britain's Guardian newspaper described the looming Rapture as "the fundamentalist Christian equivalent of the last helicopter out of Saigon," referring to the US pull-out after the Vietnam war in 1975.
The fact that Camping's predictions have been wrong before has left even high-profile people willing to make fun of him.
New York City Mayor Michael Bloomberg -- who is Jewish and therefore, according to Camping's prophecy, unlikely to be beamed up to sit alongside Jesus and God in heaven -- said on his weekly radio show Friday that he would suspend alternate-side parking in New York if the world ends on Saturday.
The much-reviled parking rule requires New Yorkers to move their cars from one side of the street to the other to allow street cleaning to be carried out.
And some are cashing in on money-making opportunities.
The Craigslist website ran tens of thousands of ads from non-believers offering to buy the worldly goods of those who think they're going to heaven, while a group of US atheists has sold hundreds of contracts to rescue people's pets.
A group of Christians who think Camping's prophecy is nonsense will be tracking the Rapture and posting reports on the Internet each time it doesn't happen.
Sceptics were planning on Twitter to create a fake Rapture if Camping's prediction does not pan out.
A tweet suggested laying out old clothing and shoes on pavements and lawns on Saturday to give the impression that someone has indeed been beamed up.