Zc024. This Biak-na-Bato National Park Caves and Trails Map is located at the entrance to the Biak-na-Bato National Park. It is a very large area, one needs at least one day to explore it and guides are available. We engaged one knowledgeable guide who was also very proud of his history. Because we had other goals we only made this a lunch stop on our trip to explore Bulacan Province.