Mohole
From Kerbal Space Program Wiki
The Mohole is a very deep hole on the surface of Moho. It is located in Moho's north and south poles. Measurments have reveald that it is about 4.6 km deep. As it goes down deeper it's walls get narrower and narrower. Once in the hole the GRAVMAX Negative Gravioli Detector will give off abnormal values[specify].
