Dubbed the ‘umbilical cord’, the Hong Kong-Zhuhai-Macau Bridge stretches 34 miles (55 kilometres) across the Pearl River Delta. The bridge is the fifth longest in the world and is 20 times longer than San Francisco’s Golden Gate Bridge.

Inaugurated by Chinese President Xi Jinping on Tuesday, the country’s latest mega-infrastructure project connects a relatively small city on the Chinese mainland with the two Special Administrative Regions of Hong Kong and Macau.

It aims to reduce travel times between China, Macau and Hong Kong, from three hours to just 30 minutes and has been built to withstand a magnitude-8 earthquake and a super typhoon.

Assistant director and senior engineer at the Hong Kong-Zhuhai-Macao Bridge Authority, Guo Xinglin, said the most technically difficult aspect was the construction of the installation of a 6.7 kilometre-long submerged tunnel.

The tunnel sits in relatively shallow waters and runs between two artificial islands, each measuring 100,000 square meters. The structure’s 55-meter high steel cylinder frames are the equivalent of an Airbus A380 – the world’s largest passenger jet.