The cost of preparing for doomsday isn't cheap.
First you have to stock up on the appropriate gear, ammunition, food and shelter to survive a nuclear meltdown, asteroid, earthquake, solar flare or some other catastrophe. Then there's acquiring the materials you'll need to rebuild a community after the dust settles.
The bottom line: Some self-described "preppers" are plunking down hundreds of thousands of dollars.
So far, Patrick Geryl estimates he's already spent more than $130,000 on his survival preparations.
Author of "How to Survive 2012" and eight other books about a catastrophe destined to occur this year, Geryl believes that a shift in the Earth's poles is going to result in solar flares, volcanic eruptions and earthquakes that will throw the world into a nuclear meltdown. The dreaded event will occur on December 21, when the Mayan calendar allegedly ends, he said.
Geryl plans to survive the turmoil in a small wooden bunker far from the nuclear radiation in South Africa, where he can live off the grid for about a year and rebuild a community with other survivors.
In order to do so, he has spent years stocking up on nearly 100 survival essentials, including guns and ammunition, water purification tablets, waterproof matches, a drafting table for charting stars in the sky -- even condoms to use for carrying water.
Books with survival tips, like a guide to edible plants, herbs and mushrooms, are also crucial, because he won't have access to the internet when disaster strikes, he said. He's still accumulating all of the necessities he'll need and is constantly adding more items to the list. [Check out his survival list here]
To get to South Africa from his home in Belgium during a worldwide catastrophe is another issue. Geryl said he is currently considering sailing there in an "unsinkable yacht," which is made by a company called Etap in Belgium. However, he said the yachts, which have double walls and are insulated with foam so that they are supposedly unable to capsize, cost more than $100,000, so he doesn't know if he'll be able to afford one.
Robert Bast, 46, is a prepper who works in Internet marketing during the day and runs an online community called Survive2012.com when he's off the clock. Bast, who lives in Melbourne, Australia, with his wife and three children, has spent more than $350,000 preparing for "the end of the world as we know it."
The end of the world, he says, could come at any time and result from any type of disaster.
"What is certain is that in my lifetime, there is a strong likelihood that there will be a catastrophe of some kind -- the sun destroying power grids, a flu pandemic that kills millions, an asteroid or meteor or comet striking earth or a magnetic pole shift," said Bast.
Bast has spent about $5,000 on stockpiles of food and water, and $11,000 on equipment including gas cookers, generators, batteries, water purifiers and solar power. He also purchased roughly an acre of land that's a 75-minute drive from Melbourne and 1,500 feet above sea level (in order to stay high and dry in case of a flood or tsunami). He has built a house there, as well as a bunker to serve as his "safe spot" in the event of an emergency. Together, the land, buildings and bunker have cost him a total of about $330,000.
He's also spent $10,000 on an 8-year old Toyota HiLux pickup truck to drive to his safe spot.
To afford all of this, Bast has been saving money from his job for years. He has a mortgage on his primary residence, and he took out a second mortgage for the home he built as his safe house.
Phil Burns, a co-founder of the American Preppers Network and the subject of "Meet the Preppers" on Animal Planet, is preparing for all types of disaster scenarios.
Among the more ominous: A natural disaster or economic collapse that causes mass starvation, causing people to become so desperate for food and shelter that they lose their minds and resort to violence. In the preparedness world, these people are often referred to as "zombies."
To ensure his survival in the event of a disaster like this, Burns, 38, has been prepping for years. He now has a year's worth of food in storage, including 4,000 pounds of wheat, beans and rice that cost about $5,000. He even has 20 bottles of different food flavorings, so that "one day I could have vanilla rice and the next I could have orange rice -- because just plain rice gets old."
He also has an RV and trailer to use as a "bug out vehicle" to get to his "bug out location,"which is a fully-stocked 40-acre retreat tucked away in the mountains of Idaho.
To protect himself from any attackers and to be able to hunt for food as a family, he has purchased several guns for each of his eight children (who learned how to shoot at age 4). Burns declined to disclose the number of guns he and his wife have, nor how much money they have spent on them.
While Burns has spent a pretty penny on his own preparations -- about $20,000 on food and guns alone -- he says that preparedness is a lifestyle and doesn't believe everyone should start spending huge amounts of money getting ready for the end of the world.
Instead, Burns advises beginning preppers to start by setting aside up to 20% of their income for preparations -- whether it goes toward supplies, emergency training classes or shelter.
Anyone can become a prepper if they are willing to dedicate the energy and resources to it, he said.
"A lot of people say preppers are paranoid, scared, pessimistic, always believing that there's going to be a disaster," said Burns. "But if you look at it with open eyes, we're actually optimists -- we're saying, 'I don't care what you throw at me, I can survive it.' "
Are you concerned that a disaster is imminent? What are you doing to prepare? E-mail blake.ellis@turner.com for the chance to be included in an upcoming story on CNNMoney. LINK