China has just holed through the world's longest undersea highway tunnel: 17.5 kilometres beneath a bay, bored by a shield machine wider than a five-storey building

China has completed shield tunnelling on what is set to become the world's longest undersea highway tunnel beneath Jiaozhou Bay in Qingdao, Shandong Province. The Jiaozhou Bay Second Subsea Tunnel is 17.48 kilometres long, with 9.95 kilometres of the tunnel lying below the water level of the bay.

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