Shanghai will transform a power station chimney into a signature attraction for the 2010 World Expo and call it the Harmony Tower to reflect Beijing's goal of building a 'harmonious society'. The 165-metre-high chimney - part of the former Nanshi power plant, which occupied the expo site for 110 years - would become an observation tower, the city government said yesterday. A helter-skelter running around the chimney will carry 300 passengers at a time. It won't run as fast as a circus ride, though - the round trip will take nearly half an hour. Planners envision the tower will resemble Shanghai's official flower, the white magnolia. The company developing the project, Zhejiang Juma Amusement Equipment Manufacturing Factory, is building what is said to be the world's largest Ferris wheel in Beijing, a Zhejiang newspaper reported. The expo organiser signed the contract for the project yesterday. The observation tower, on the west bank of the Huangpu River, will be the tallest structure on the expo site. It will be completed in January 2010, ahead of the start of the expo in May. The Shanghai government had already said it would redevelop 380,000 square metres of old industrial sites for the expo, including turning a massive dry dock into an outdoor theatre. The city began building the expo's China pavilion, which resembles a crown, last month. The former power plant below the tower will become a 9,000 square metre pavilion for 'exploration of future cities'. A bridge formerly used to carry coal to the plant will get a new life as a promenade extending to the waterfront. The closure of the power plant and the reuse of its buildings are intended to highlight environmental protection and historical preservation, two of the expo's themes.