When there wasn't any work to do, many Marines created some and the threat of enemy tunnels provided a powerful motivation. When the word spread that the enemy might try to dig under the base, the tunnel ferrets went to work. Many of the defenders became fascinated with the prospects of uncovering a "mole" and their antics were near comical. It was not uncommon to see a man crawling around in front of his position, patting the ground with the flat side of a shovel, and listening for hollow spots. Others drove metal stakes into the ground and listened with stethoscopes by the hour for tell-tale signs of digging. If they heard something, the next step was to dig a large hole in front of the enemy so that he would tunnel himself into a trap. Some self-appointed water witches walked around with divining rods and waited for the downward tug which meant that they had discovered a subterranean intruder. When the news media got into the act and publicized the possibility of tunnels, the regimental commander began receiving scores of letters from around the world with "If I were you" themes. One American planter who lived in Sao Paulo, Brazil, wrote and suggested that the Marines purchase commercial sensors like the ones he used to detect bugs which fed on the roots of his trees. Another suggested that the defenders strap hand grenades onto rats and turn them loose in the tunnels.(175) Unknown to the Marines at the time, the enemy never tried to tunnel under the base. The KSCB sat atop a plateau, and the slopes were wrinkled with deep ravines. Colonel Lownds later surmised that the enemy would have had to go so deep to keep from breaking the surface that such excavations were impractical. The men of Company K, 3/26 did, however, discover one tunnel leading toward Hill 861 and called in air strikes against it; at the base itself, the North Vietnamese limited their digging to trenches.(176)