What investment would be immune from a stock market crash?

NO investment is immune. Some are more stable than others, but everything gains value from supply and demand, and therefore is susceptible to a depression or stock market crash. Gold is easily the most stable, I would say, but golds' value fluxuates constantly, and in the case of a stock market crash as bad as the late 20's, people would want to buy bread more than gold, and the value would plummet.
That having been said, the value of gold would plummet less than paper money, so investing in gold would be the best option, but don't kid yourself; no investment is immune, no investment is fool-proof.

Gold's at the apex of a 20 year high too, so investing in it right now would likely bankrupt you if you intend to keep it for anything less than 30 years,.

something that someone will always need maybe water i really dont know but i tried.

Gold, government bonds...........

gold

gold
or you could buy SKF, an inverse financial ETF that will go up if the dow tanks.

Placing a sell bet before it happens !

Premium Bonds, no interest, but cannot lose any money. Get put in a prize draw every month for a million quid.

Invest inYOURSELF.

Go to : low-cost-stock-recommendations

.com

Click on the "DRIP's" Button on the Navigation Bar

These long-term investment plans are one of the least known investment strategies on Wall Street. If you are in these plans long-term, you will not care if the market is up or down, as your money will automatically dollar cost average.

If you decide you are interested, click on the "ING" advertisement on the same page. It wil answer your next question.....which is......how do I get started?

Good Luck

Nothing is immune from a big stock market crash unless you store it under your mattress! Gold is good but if we had a real market crash, not too many people will have the money to buy it.

Money Market fund, high quality bond, medicine/food, precious metal/jewel, money (from a strong market)

There really isn't an immunity per-say, but these kind of investment are less affected by recession and crash.

Being short the market.

Assuming a crash as bad as 1920's, I would suggest you go out and fill your House up with canned food and firearms.

I see tons of advices but all outside of the stock-market. Not necessarily! I would not rule out some 'sectors/segment' within the stock market which will be acting inversly in the opposite direction during a general stock market crash. Meaning, when there is a stock market, the 'broader market' segment will be directly affected but there would be certain notable sectors that remain clearly immune or even work inversly (depending on the nature and cause of the stock market crash). You will have to have some degree of knowledge and familiarity in order to identify or even to do the right research or analyise reports/news to find these investments. I don't claim to be an expert, but sure know what I dont' know!
Here is one example of what I dont' know. There is a new category of investments that are extremely becoming pupular these days (say since 2005 - 2006) , called the inverse or shorting ETFs. I DON"T KNOW if these fall into that category. I think they are as volatile as the 'stocks' and not necessarily immune but they tend to go the opposite direction of the general stock trend.
http://seekingalpha.com/article/28715-no...

gold

-Place it in a shoe box under your bed... but even then with the devalued dollar.....

This is a difficult one. If you look at the historical facts you will find not many investments escape a crash, maybe a couple of per cent. Oviously you could buy puts, or go short if that's what you meant.

i would say the only thing that could stand a good chance of not crashing completely would be a mutual fund or a etf. Try vanguard been around for a long time and has very good returns.

gold and silver

High tech Aim stocks and very highly geared company's about to go under.

When the market really tanks nobody will be holding these type of stocks so they will have nowhere to go but up.

I made $6,000,000,000 last tuesday just before getting up.

Cash in the bank would have no response if markets fell.

Other investments that people have recommended do fluctuate in value, albeit not completely correlated with the market.