Traveling underground was an experience unto itself. Once he got over the fear that his soul would crash into something, and actually sped up, he discovered that there was a lot more to the underground than just endless dirt and rocks.
There were so many plants, not even counting the extensive root network for whatever plants could bury roots so deep. There were living creatures with underground colonies that gave Lex wonderful ideas for his own Inn. There were more than just a few underground rivers with water to clean and cold, Lex actually felt tempted to stop and take a drink.
Eventually Lex spread his soul sense out as well, and was amazed at the fact that life was thriving just as much this deep underground as on the surface.
Lex also found something he completely would never have expected. A massive network of chambers had been excavated to create somewhat of an abode, and it was covered in remnants of protective formations.