"Concrete gold"- that's investor slang for real estate, which offers security in times of crisis. And investing in real property could pay off in the big cities. In Cologne, for example, prices are rising.Now, an increasing number of apartments are being snapped up before they’ve even been built. And many investors, leery of the stock markets, are buying land and buildings. Our reporter Marion Hütter met with courageous buyers and happy real estate agents in Cologne.