The world’s longest sea-crossing bridge opened in China on Tuesday, connecting the semi-autonomous territories of Hong Kong and Macau to Zhuhai city in mainland China, the BBC reported. The bridge spans 55 km, including its access roads, and was inaugurated by Chinese President Xi Jinping.

China is also home to the world’s longest bridge, the 165 km-long Danyang-Kunshan Grand Bridge between Shanghai and Nanjing, reported the CNN.

Xi and other leaders of Hong Kong and Macau attended the opening ceremony in Zhuhai. The bridge is part of China’s plan to create a Greater Bay Area, including Hong Kong, Macau and nine other cities in the country’s southern region. It is expected to reduce travel time between the cities from three hours to 30 minutes.

The construction of the bridge started nine years ago and cost about $20 billion. Around 400,000 tonnes of steel, enough to build 60 Eiffel Towers, were used to build the bridge designed to withstand earthquakes and typhoons. It will open to regular traffic on Wednesday.

Chinese Vice-Premier Han Zheng said the bridge will bring Hong Kong and mainland China closer in terms of trade and economic activities, reported the South China Morning Post. It was described as a sign of successful cooperation between mainland China, Hong Kong and Macau and as an example of China’s engineering capabilities.

However, local media has described it as the “bridge of death” following the deaths of at least nine workers on the Hong Kong side and an equal number in China. Hundreds of workers were also reportedly injured during the construction.