Mount Apo is a large stratovolcano on the island of Mindanao in the Philippines. This is the tallest and mightiest mountain in the Philippines, with a height of 10,311 feet above sea level and a total area of 14.6 square kilometers. Its name means "master" or "grandfather". Apo is flat topped, with three peaks, and is capped by a 500 m wide volcanic crater containing a small crater lake.