CHENGDU, Sept. 28 (Xinhua) -- The Jiajin Mountain Tunnel, a 9.35-km passage beneath the first snow mountain crossed by the Central Red Army during the Long March in 1935, was completed on Sunday, and will begin trial operation on Oct. 1.

This tunnel reduces the crossing time from one hour to just 10 minutes, ending decades of winter isolation for the 110,000 residents in the surrounding areas.

In June 1935, the Central Red Army braved extreme conditions atop the 4,000-meter-high Jiajin Mountain, successfully crossing it with unwavering perseverance and determination during the Long March.

The new tunnel, constructed using innovative technologies, set national records for efficiency despite high-altitude challenges.

The project will boost regional tourism and economic integration, and facilitate cultural exchanges among ethnic groups, a local official said.