The police followed tread marks to the location of the apparent excavator in question and arrested two people — a 38-year-old man and a 55-year-old woman working at a nearby construction site. They are suspected of using the excavator to widen an already existing gap in the wall, destroying a strip of the ancient structure to create a shortcut, according to a statement from the Youyu County Public Security Bureau, CCTV reported.

The two were summoned for further investigation. Their actions, police said, have caused “irreversible damage to the integrity of the Ming Great Wall and the safety of cultural relics.”

The Great Wall of China, named a World Heritage site by UNESCO, is considered among the most outstanding examples of ancient human engineering and perseverance. It was erected and fortified over more than 1,800 years, beginning around 220 B.C., according to UNESCO, in a process that continued until the demise of the Ming Dynasty in the 1640s.

The sections built by the Ming Dynasty, which include the newly damaged section of the 32nd Great Wall, are ambitious feats of construction.

The wall functioned as a barrier against nomadic groups of the vast steppe north of China, historians say.

Some 30 percent of the stone fortifications, which run thousands of miles, is crumbling into ruin, according to National Geographic.

Correction: An earlier version of this article reported UNESCO’s claim that the Great Wall is “the only work built by human hands on this planet that can be seen from the moon.” It cannot be seen unaided from the moon, although other results of human activity can be seen, NASA has specified. The story has been corrected.