The great Sierra Madre lockdown | The Manila Times
THE island of Luzon is traversed by three mountain ranges. Its geological spine, the Sierra Madre Mountain Range, is a 540-kilometer stretch from Cagayan to Quezon. The Cordillera Mountain Range, measuring 320 kilometers cuts through Nueva Vizcaya, Quirino and Nueva Ecija, and between the two is the Carballo Mountain Range. These three nurture the headwaters of the mighty Cagayan River. The Sierra Madre and Cordillera were so impenetrable, the Spanish empire could barely stake territory with Cross and Sword.