While, I agree that you should not invest in anything you do not understand, no matter what the returns are ( I am not talking about gambling) and what you can have control upon.
I am afraid you never have control with stock market. Reasons, funds managers control it. Sectors come and go and until you dont have team of spealist on each sector of the stock market events can over take. Not to mention political, (e.g Govt restriction on foreign holdings Rolls Royce and Rail track) /world events. World events may recover with time.
Futher, money is made from other money i.e. the Banks. they will not lend you to buy into stock market.
Property is a prudent way to invest and with banks money. To spread the risk you can invest in different countries. e.g recent % gain predictions.
UK 6-7%, France 9-10%, Poland 12%, Spain& Italy 7%, morocco 15%,
If you take an average return of say 10%, on borrowd money, without lifting a finger.
I, understand this a simplistic, but I dont want the forum readers to go to sleep.