Before you invest any money, I think you need to get a clear view of your requirement. You were considering buying property but you also say you want your money to be completely safe. Those two contradict each other. Property is far from safe. The value of property can go up or down, it is illiquid and rental income can fluctuate a lot.
In a broad sense, the "safest" place for your money would be to put it on deposit with the strongest financial institution(s) out there. But even that's not completely safe. Aside from the possibility of the collapse of the institution, there's the more likely possibility that the rate of interest you achieve won't keep up with inflation. So the earning power of your lump sum will be eroded over time.
Before looking at specific financial products, remember this. If you want the prospect of a higher return than what you can get by keeping your money in cash, you must accept a higher level of risk. Risk and return are inextricably linked.