The world's third-biggest oil producer is also blessed with vast reserves of gas, fresh water and fish. Norway is Europe's Saudi Arabia: a country so wealthy that despite having a population of just 4.5 million, it is a major player on the world stage. But as the frozen north melts and the competition for oil and gas intensifies, the country is keeping a watchful eye on neighbouring Russia. And at home, prosperity is creating its own worrying problems.