Upon reaching the stone wall, Leonard Ethan and Fairmont immediately took out their small shovels and started to clean the substances adhering to the stones. Soon, a distinctive stone wall that differed from its surroundings was revealed.
"This stuff seems like cement." Fairmont, looking at the smooth surface on the stone, displayed a look of curiosity. "Isn't cement a modern invention?"
"In fact, in 1824, a British construction worker Joseph Aspden invented the first version of modern Portland cement and obtained a patent. Not to mention that the Ancient Romans used a kind of volcanic ash cement."
Leonard Ethan spoke while inspecting the layer of cement on the rock wall and the surrounding areas. "If I'm not mistaken, this should be a hidden space that was created using a natural crack in the stone wall and coated with cement."
