Unexpected discovery

Log 24 : 36 km in , we've been in this tunnel for 3hours and half . We still don't have reception from the surface so we keep going on , that was expected anyway , so deep underground .
Log 25 : 38km in , Ellie is overly excited , carving on the walls start to reappear as we go forward , it's a nice change after 4 hours of blank dull walls .
Log 26 : There is ... a light ... blue... definitely artificial ...what the F@#... it can't be... the entrance has been buried and sealed for thousands of years...