Bitcoins are created as a reward in a competition when a computer solves a certain kind of puzzle. The process is called 'mining', and it has created a virtual gold rush. Marco Streng is a mathematician and businessman from Munich who runs a mining farm in Iceland. He won't disclose any numbers, but he is evidently making money. Just the electricity needed to operate all the hardware costs a million euros a month. Bitcoin is traded like a standard currency nowadays and the exchange rate fluctuates -- sometimes wildly.