These are one of the Seven Natural Wonders of Portugal and the greatest in the country. The entry to the caves is impressive: as you can see from the name, the Big Room is a large space with stalactites and stalagmites of all shapes and sizes.
Then you will go all the way down reaching a depth of 360 feet. During this visit you can also see limestone formations such as the Jellyfish, the Small Lakes, the Martian, the Boca do Inferno (Hell’s Mouth), and the Organ. The Black River winds along this cave and flows into the Great Lake. At the end of the visit, there is a show of light, sound, and water.