Almost on every mission the astronauts did some digging, but how deep did they reach? According to this article:
The regolith is generally from 4 to 5 metres thick in mare areas and from 10 to 15 metres in the older highland regions. Below this true regolith is a region of blocky and fractured bedrock created by larger impacts, which is often referred to as the "megaregolith".
So did they ever see what was beneath the regolith?