California preacher Harold Camping said today his prophecy that the world would end was off by five months because Judgement Day will actually come on October 21.
Mr Camping, who predicted that 200 million Christians would be taken to heaven on Saturday before the Earth was destroyed, said he felt so terrible when his doomsday prediction did not come true that he left home and took refuge in a motel with his wife.
His independent ministry, Family Radio International, spent millions - some of it from donations made by followers - on more than 5,000 billboards and 20 vehicles plastered with the Judgement Day message.
But Mr Camping says he has now realised the apocalypse will come five months after May 21, the original date he predicted. He had earlier said October 21 was when the globe would be consumed by a fireball.
It is not the first time the independent Christian radio host has been forced to explain when his prediction did not come to pass. He also predicted the Apocalypse would come in 1994, but said it did not happen then because of a mathematical error.
Rather than give his normal daily broadcast yesterday, Mr Camping made a special statement before the press at the Oakland headquarters of the media empire that has broadcast his message.
His show, Open Forum, has for months headlined his doomsday message via the group's radio stations, TV channels, satellite broadcasts and website.
When the Rapture did not arrive on Saturday, crestfallen followers began turning their attention to more earthly concerns.
Jeff Hopkins thought the petrol money he spent driving back and forth from Long Island to New York City would be worth it, as long as people could see the ominous sign atop his car warning that the end of the world was nigh.
"I've been mocked and scoffed and cursed at and I've been through a lot with this lighted sign on top of my car," said Mr Hopkins, 52, a former television producer who lives in Great River, New York.
"I was doing what I've been instructed to do through the Bible, but now I've been stymied. It's like getting slapped in the face."
Apocalyptic thinking has always been part of American religious life and popular culture. Teachings about the end of the world vary dramatically - even within faith traditions - about how they will occur.
Still, the overwhelming majority of Christians reject the idea that the exact date or time of Jesus' return can be predicted.
Tim LaHaye, co-author of the best-selling Left Behind novels about the end times, recently called Mr Camping's prediction "not only bizarre but 100% wrong!". He cited the Bible verse Matthew 24:36, "but about that day or hour no one knows" except God.
"While it may be in the near future, many signs of our times certainly indicate so, but anyone who thinks they 'know' the day and the hour is flat out wrong," Mr LaHaye wrote on his website, leftbehind.com.