Thump.
A long ladder was placed against the wall. Mu Zhiyang climbed up first to test its stability, then came down and handed it to Jiang Yuan. He also secured a safety harness for Jiang Yuan.
Jiang Yuan climbed up without hesitation, taking a hoof mirror with him.
The traces on the wall mainly fell into several categories: some formed naturally, such as moss, peeling paint, discoloration caused by varnish, erosion from rain, and other reasons. Others were caused by clothing, leaving smudges and contact marks. Lastly, there were marks resembling footprints.
Jiang Yuan needed to set aside the first two categories and focus on examining the latter two.
He scrutinized them attentively, at one point tilting his body to a 90-degree angle with the ladder.
Shen Yaowei ordered another safety rope to be lowered from mid-air so that Jiang Yuan could use it to steady himself.
