The underground river attraction you are referring to is most likely the Puerto Princesa Subterranean River National Park, also known as the Puerto Princesa Underground River. It is located in the province of Palawan, Philippines. The Puerto Princesa Underground River is a UNESCO World Heritage Site and one of the New Seven Wonders of Nature. It is a 8.2-kilometer (5.1-mile) river that flows underground through a cave system before emptying into the South China Sea. The river is known for its stunning limestone karst formations and unique ecosystem. Inside the cave, you will witness a breathtaking display of stalactites and stalagmites, along with other intriguing geological formations. The boat tour is guided by trained personnel who provide information about the cave's history, geology, and wildlife.

Wildlife Spotting: The national park is home to a diverse range of wildlife. Keep your eyes peeled for various species of birds, reptiles, and monkeys along the riverbanks. With luck, you may even spot some bats hanging from the cave ceiling. The park is surrounded by lush rainforests and stunning limestone cliffs. Take in the breathtaking natural beauty as you cruise along the river. You'll be treated to picturesque views of the forest, limestone formations, and the emerald-green water.