The tunnel was about 20 meters high and more than 10 meters wide. It was a roughly oval shape. Its walls were all black and brown hard rock. No one knew whether it was a natural tunnel or an artificially excavated tunnel, and after years of invasion, it became like this.

The deeper they went, the lighter the wind was.

A deep and remote cold Icing air, as if it was from underground, enveloped everyone.

Liu Suifeng walked in front of the crowd with a ...