A crystal-clear river flowing through dramatic limestone canyons in Nagtipunan, Quirino Province, offering one of the most scenic river tubing and kayaking experiences in the Philippines. The river's blue-green waters are so clear that the rocky bottom is visible even in deep sections. Combined with the surrounding cave systems and waterfalls, it creates a premier ecotourism destination in northern Luzon.
| Category | Nature |
| Province | Quirino |
| Region | Region II - Cagayan Valley |
| Coordinates | 16.32000000, 121.52000000 |