The presence of numerous immersed caves in Valbrenta offers the possibility of interesting cave diving explorations. Starting from the south, in the area of Solagna, the karst spring of Fontanazzi is a destination for caving enthusiasts, which allows them to enter a unique zone. Continuing north and entering the town of Valstagna, the underground system of the Caves of Oliero is most important karst phenomenon in the whole valley, followed by the complex world of the Subiolo Caves, located a few miles to the north. In the Cave Park of Oliero there are two "covoli" available visit; the 'Covol dei Siori' or the Parolini Grotto and the "Covol dei Veci". The cave diving explorations are very frequent in these two "covoli" visited both by the enthusiasts of submerged caves, and by real experts.