Fireworks illuminated the Shanghai skyline in a blaze of colour as China kicked off the six-month World Expo on Friday with a lavish star-studded opening gala attended by a host of world leaders. Still basking in the glory of its successful staging of the 2008 Beijing Olympics, China is treating the Expo as an equally important showcase for its growing political and economic clout. <br/><br/>From the United States to North Korea, a total of 189 countries will take part in the six-month display of ideas, culture and technology expected to attract at least 70 million visitors – the vast majority of them Chinese. <br/>