Dear Namdrol,
Firstly, I would like to thank you for this picture. What a blessed and sacred picture of a spot so holy. Thai monk made a great comment, in that "If Je Pabongka spoke of the Lam Rim there, it should be equal to Bodhgaya, the place of Lord Buddha's enlightenmnent." The Lamrim is one's guide on the path to enlightenment, so if it is relied upon to bring one to enlightenment, then it holds such significance as well. So this is the root where it all happened. Exciting!
So many practitioners today base their learnings and practise from the book Liberation in the Palm of your Hands, that was compiled by Kyabje Trijang Rinpoche from the oral discourse that was given by Pabongkha Rinpoche. To think that at first Pabongkha Rinpoche was not "the brightest of students", and eventually being able to give such a historical discourse, goes to show how we always use our judgements to judge others, instead of helping them. Luckily Pabongkha Rinpoche's guru had him meditate in the cave after giving him short teachings of the lamrim, otherwise, we would not have this great text with us today.