The remarkable feat of building the tunnels by hand. The entire system was dug manually using only simple farming tools such as hoes, shovels, and bamboo baskets. Thanks to the special characteristics of the clay mixed with laterite, the tunnels became extremely sturdy and rarely collapsed. The digging process was carried out in small groups, with each person assigned a specific task. One person would crawl directly into the tunnel to dig deeper into the earth. Because the tunnels were extremely narrow and dark, this work required extraordinary strength and patience. Once a certain amount of soil was dug out, it would be placed into a bamboo basket or cloth sack. Another person, standing at the mouth of a vertical shaft, would use a rope to pull the soil up to the surface. The soil was then carried away by yet another person. Instead of dumping it all in one place, they cleverly scattered the soil across various locations – under dense bushes, in ponds, rivers, or mixed into farmland soil. This prevented the formation of large mounds that could raise suspicion. Once a tunnel section was completed, the entrance was sealed with a wooden trapdoor, hinged and covered with soil and dry leaves. The entrance was so small that only one person could crawl through at a time. To ensure air circulation inside the tunnels, villagers built secret ventilation shafts. These vents, made of bamboo or other materials, extended from the tunnels to the surface and were cleverly disguised as termite mounds or tree stumps