Workers work 40 meters underground in the Lanzhou section of the Yellow River, capital of northwest China’s Gansu province, May 9, 2016. The construction of the right tunnel of Lanzhou subway line one was completed on May 9. It’s the first subway line to run under the Yellow River.

Workers work 40 meters underground in the Lanzhou section of the Yellow River, capital of northwest China’s Gansu province, May 9, 2016. The construction of the right tunnel of Lanzhou subway line one was completed on May 9. It’s the first subway line to run under the Yellow River.

Workers work 40 meters underground in the Lanzhou section of the Yellow River, capital of northwest China’s Gansu province, May 9, 2016. The construction of the right tunnel of Lanzhou subway line one was completed on May 9. It’s the first subway line to run under the Yellow River.

Workers work 40 meters underground in the Lanzhou section of the Yellow River, capital of northwest China’s Gansu province, May 9, 2016. The construction of the right tunnel of Lanzhou subway line one was completed on May 9. It’s the first subway line to run under the Yellow River.