FACTBOX-Key facts about the Shanghai World Expo

(For a story on the Shanghai World Expo, see [ID:nTOE63S024]

SHANGHAI, April 30 (Reuters) - Here are some key facts about the Shanghai World Expo taking place between April 30 and Oct 31.

* Shanghai's World Expo, themed "better city, better life", will showcase the latest green technology from 191 countries taking part.

* The first developing country to hold an Expo, China is making a great effort to promote the event as environmentally friendly, creating the country's largest solar plant as part of the facilities and using zero emission vehicles for transportation. But most of the exhibition sites will be demolished when the Expo ends.

* China says it has spent $4.2 billion -- double what it spent at the 2008 Beijing Olympics -- to host the world's largest exhibition. It is the most expensive Expo to date and local media have reported the true cost is closer to $58 billion.

* The size of the Expo site is twice the size of Monaco and 20 times bigger than the last World Expo held in Spain's Zaragoza in 2008. The site spans 5.3 sq km across both sides of Shanghai's murky Huangpu River.

* Shanghai allocated $45 billion to upgrade the city's infrastructure, creating the world's longest metro system, two new airport terminals and a $700 million promenade on the historic Bund as well as new roads, parks and bridges.

* Shanghai expects 70 million visitors will attend the Expo, though just 5 percent will be foreigners. The city has dramatically increased security measures with bag checks at every subway station and bomb-recognition pamphlets distributed to offices in the Pudong financial district.

* The city has adopted a blue molar shaped mascot called 'Haibao', meaning treasure of the sea. Created from the Chinese character for people, it is meant to represent human beings playing a positive role in developing a better city. (Writing by Farah Master; Editing by Ben Blanchard and Sanjeev Miglani)