Lake Kayangan in Coron, Palawan is said to be the cleanest lake in the country. Surrounded by limestone cliffs, this beautiful picture-perfect scenery can be reached after a walk up a mountain trail. Kayangan Lake is one of Coron’s primary attractions. Accessible by a steep 10-minute climb, the crystal-clear waters of Lake Kayangan are nestled into the mountain walls; underwater is like a moonscape.