Second Taiwan Strait Crisis
The tunnel was constructed in 1969-1971 by the Republic of China Armed Forces for ships to avoid bad weather and attacks from the People's Liberation Army in the aftermath of Second Taiwan Strait Crisis in 1958. It took 820 days for the tunnel to be completed which were mostly done by hand, with some exception of small amount of explosive. Some of the workers lost their lives during the construction process. At that time, the tunnel could harbor 120 small naval vessels but it was badly damaged after a severe typhoon hit the area.