a UNESCO World Heritage Site and one of the New 7 Wonders of Nature.
The 8.2-kilometer river,the longest navigable underground river in the world
The entire area where the Underground River is located is actually a national park and a model of biodiversity. More than 800 plant species, including almost 300 trees, 195 bird species, 30 mammals, 19 reptiles, and eight bat species call this area home.