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.br br From the United States to North Korea, a total of 189 countries will take part in the event of ideas, culture and technology expected to attract at least 70 million visitors - the vast majority of them Chinese.br br It is the first time a developing country has been chosen to host the event, and the city has undergone a massive face-lift at a cost of $45 billion in preparation for the Expo.br br Al Jazeera's Divya Gopalan reports.