The TACCHI are calcareous dolomite mountains so called for their shape similar to the heel of a shoe, Perda ‘e Liana being the most representative and famous one. This particular mountains are crossed by tracks and lanes which in the past represented the thoughways to the people living here. Tacchi’s area lies mainly on the territories of Ulassai, Osini, Gairo and Ussassài. Among the places censed as natural monuments, besides the already quoted Perda ‘è Liana, are La Scala S.Giorgio, the Su MURMURI Cave, Monte Tisiddu, Monte Pranedda and the spectacular Serra Perdu Isu a Taquisara. Perda ‘e Liana Lies in the teritory of Gairo and is Sardinia’s most famous natural monument. It rises up to almost 1300 metres and a legend says that it represented one of hell’s gates from where devils and witches came out, whoever wanted to become rich had to come to this location and offer their own soul to the demon. Extremely important from a geological point of view, the Tacchi d’Ogliastra area offers findings of beautiful calcite and dolomite crystals, many other minerals, corals and fossils already in the first calcareous layer. From a botanic point of view the Tacchi’s most typical environment is the mediterranean undergrowth and the evergreen oak groves, the wildlife has as its protagonist the Royal eagle, even if it is not rare to see voltures, besides endemic imperial crows, the largest among Europe’s crows, the wood pigeon, the ina, among the night birds of prey are the sardinian screech owl, the kertrel, the buzzard and the little sardinian horned owl. The pilgrim hawk nests among the rocky gorges. The rivers are populated by sardinian trouts and eels, besides water snakes and anphibians. Coccoronis and Mela are among the important nuraghic sites present in the area. Also noticeable are Serbissi nuraghic area, Truculu village, Perdu Isu and Didu villages in Montarbu Forest, where you can see the Taccu Addai nuraghe at Is Tostoinus, The funeral monuments on the contrary are rare in the area, in total four , plus a fifth one found in the plain under Serbissi. The first two are in Truculu’s archeological site near Sany nuraghe, a third one on mela plain, the fourth included in Is Tostoinus village near Taccu Addai nuraghe and the fifth one near Funtana Noa under Serbissi nuraghe. Among the caves present on the territory, De Su Marmuri cave is undubtley the most famous, the most important for beauty and greatness of the environment. You can reach it leaving from Ulassai, where you take a road heading towards Tacchi. After a few curves you arrive at a large square from where you continue on foot. Equipped and well-lit flights of stairs and foot bridges allow a good view of the large halls which can be visited from April to October. Other interesting caves are Is Lianas, of great biospeleological interest, Sa Brecca Andriana called Voragine punta S’assa Bella, near Ulassai village, and Grotte di Taquisara above the homonymous village.