Part of the Biak na Bato cave system. Biak na Bato means Broken Stone. The during the revolt against Spain, some revolutionaries like Emilio Aguinaldo hid in these caves.
Lots of limestone formations in these 2 mountains, similar to Mt Daraitan in Rizal province. Because of the rains, the stones were slippery and trail was muddy, making the climb more difficult. I have new bruises on my knees. Note to self - buy some knee support thingies.