A huge turbine was at the top of the space, occupying his vision. Around the turbine was a dark red laser light curtain, similar to the outer city walls. An Zhe knew that this was one of the human defense systems. If a creature wanted to forcefully pass through it then an alarm would trigger.

He looked through the iron teeth of the turbine and saw the sky outside where the aurora was still shining. This place was connected to the outside world and An Zhe realized it was the air inlet of the ventilation system. Once the turbine started, the outside air would be continuously drawn in and transported through the pipes in all directions.

An Zhe retracted his gaze and looked forward. In the centre of this cylindrical space was a rectangular metal workbench. It was probably the operating platform of this entire system. He went up to it but found this wasn’t the case.

On the metal table, there were three rectangular boxes and mottled handwriting next to the small boxes which seemed to be plated. An Zhe slightly leaned over and wiped away the dust and rust to read the writing.

It was a letter.

To the latecomers:

I am Kang Jinglan, the head of the underground ventilation system’s engineering construction team in the Northern Base. The ventilation system took one year to design and nine years to construct. The cost was 110 million yuan per kilometer.

Opponents have suggested that the construction period be postponed because of the difficulty of the base construction and the huge amount of manpower and resources consumed. However, after discussion, we believe that once the weakening of the geomagnetic field continues, the human economy will inevitably collapse with 10 years. Within 50 years, the surviving humans will completely lose the R&D production capacity for heavy industry and the focus of production materials and scientific research will be tilted to the medical field. We have no time.

Fortunately, this year the underground ventilation system was successful completed together with the above-ground base. Fellow humans can now live in the tight protection of the base. This is the only thing I am happy about. Due to the cosmic radiation, despite being tightly protected, I still suffer from a variety of cancers and immune system diseases. I have asked the base to keep my ashes at the core of the ventilation system, so that for every generation of engineers entering for the system maintenance, I will know that the base is still safe and the great species of humanity is still alive.

May you have a bright future.

Sincerely.

Salute.

June 2030.”

These were the ashes. So the remains in this box were once a human body. It was a tomb and these writings were a legacy the human left for later people. It was perhaps more appropriate to call it a epitaph.