World’s longest spiral tunnel with three loops nears completion in China

The world’s longest spiral tunnel is nearly ready in China's central province of Henan after the breakthrough for its main section was completed on October 8, 2022. When finished, the nearly 4.5 kilometres (2.8 miles) road will pass through a mountain after completing three loops and form part of a key expressway that is scheduled to open by the end of 2022.