Surrounding the southern edge of the Sierra Madre range and located a few kilometers from San Miguel Bulacan, Biak na Bato is one of the country’s ecological and historical treasures. Literally known as “split boulders,” it was the mountain hideout of the Filipino revolutionary forces during the Spanish regime. It was where the historic Republic of Biak-na-Bato was established and where the Malolos Constitution was signed by Gen. Emilio Aguinaldo and Pedro Paterno.