Harold Camping really believes the world is going to end.

And while you may not personally buy into the May 21 judgment day prediction, the California-based religious figure and radio broadcaster has followers around the world preparing for the impending rapture.

Who is the man behind the movement? For a quick review, here are five facts on Harold Camping.

1. He's originally from Colorado.

Camping was born July 19, 1921 in Colorado, but moved to California with his family at a young age. He eventually earned a B.S. in Civil Engineering from the University of California at Berkeley in 1942.

2. He started Family Radio in 1958.

After school, Camping established himself in the construction business before forming and becoming president of the non-profit ministry of Family Stations, Inc. Three years later, the organization introduced the Open Forum, a live, weekend radio program hosted by Camping.

3.He already wrongly predicted the rapture once before.

Camping has written approximately 30 books, and "1994?" -- which contains his infamous prediction that the rapture would take place sometime during mid-September, 1994 -- is perhaps the most well-known among them.

By the way, you can get all of Camping's works for free on the Family Radio website.

4.Even so, he's pretty sure of himself this time around.

When asked by New York Magazine whether he would start getting nervous if "six o'clock rolls around" nothing is happening, Camping responded, "It’s going to happen. It’s going to happen. I don’t even think about those kind of issues. The Bible is not — God is not playing games. I don’t even want to think about that question at all. It is going to happen."

5. He has more than a few doubters.

While Camping does have his share of followers -- maybe you've seen the billboards and buses -- he also has his share of detractors. For instance, the folks at RefuteCamping.com.

For more, here's Camping responding to a caller who doesn't buy into the May 21 rapture.

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