One fringe group has gained national notoriety with their predictions that the end of the world will be this May 21, but just how did they arrive at that conclusion?

The Oakland-based Family Radio Worldwide said they have crunched the numbers and have done the math, with the groups president Harold Camping declaring the event absolutely going to happen.

The Bible lists very few specific dates for events, so calculating Judgment Day is a daunting task. How could the network come up with such a specific date?

It turns out the basis to the math hinges on the apocalyptic flood that comes out in the book of Genesis.

That flood, which the Bible records as wiping out man-kind sans Noah and the others specially selected, is the basis for which all other Camping derives.

Prior to the flood the Israelites fled Egypt in what many scholars believe to be in 1447 B.C.. From that date Camping counts back generation by generation and arrives at the year 4990 B.C. for the flood.

The accuracy of this date is paramount to Camping's argument. Some biblical scholars say the flood happened around 2000 B.C.

Another key is taken from the flood as well: that the people of those days had exactly 7 days to prepare before the destruction came. From that time the current world is given a period of 7 to prepare -- but this time 7000 years.

But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day, reads 2 Peter 3:8.

Using the seven-day warning as a benchmark, Camping's calculations take this passage to heart. He added 7,000 years to the great flood date of 4990 B.C. to determine the date of the next destruction of humanity.

That would put us in the approximate millennium but what about the day?

Camping relies on Genesis 7:11, explaining that the flood occurs on the seventeenth day of the second month, or 17 Iyar of the then standard Hebrew calendar.

Thus May 21, 2001.

Of course there maybe room for error in his prediction. Even the Bible says that no one knows the date, not even Jesus.

Camping predicted the same situation before - in 1994 - and 17 years later, we're still here.