The Apolaki Caldera, located beneath the Philippine Sea, is believed to be the largest known volcanic caldera on Earth — spanning roughly 150 kilometers in diameter. It lies on the Benham Rise (Philippine Rise), an underwater plateau east of Luzon.. This enormous structure is part of the Pacific Ring of Fire, a 40,000-kilometer horseshoe-shaped zone that encircles the Pacific Ocean and hosts 75% of the world’s active volcanoes and 90% of its earthquakes. The Apolaki Caldera’s location connects t