China has opened the longest sea-crossing bridge ever built, nine years after construction began. The Hong Kong-Zhuhai-Macau Bridge connects Hong Kong and Macau to the mainland Chinese city of Zhuhai. The $20-billion bridge spans 55 kilometers.
The bridge, designed to withstand earthquakes and typhoons, has been built using 400,000 tonnes of steel, enough to build 60 Eiffel Towers. Estimates suggest the bridge will be in use for 120 years but there are likely to be restrictions on usage.