In 2010, a group of environmentalists and geologists discovered that the underground river has a second floor, which means that there are small waterfalls inside the cave. They also found a cave dome measuring 300 m (980 ft) above the underground river, rock formations, large bats, a deep water hole in the river, more river channels, another deep cave, as well as marine creatures and more. Deeper areas of the underground river are almost impossible to explore due to oxygen deprivation.[clarification needed]
On November 11, 2011, Puerto Princesa Underground River was provisionally chosen as one of the New7Wonders of Nature. This selection was officially confirmed on January 28, 2012.