Landscapes are usually considered as complex systems of superficial natural landforms covered by a more ore less developed and diversified land-cover (vegetation, agricultural and human elements). These territories are usually sorted in more or less homogeneous landscape units reflecting different intrinsic (natural and geological) characters and distinct ways of utilisation of the soils.
Among all landscapes, the karstic ones are probably the most interesting and fascinating, also because the "landscape" continues underneath the topographic surface. In fact, where in other lithologies human exploration stops at the surface - except in mining regions where artificial voids have been made by Man - in karst areas extremely complex cave systems have sometimes developed, forming a unique subterranean landscape with its own characteristics and peculiarities.
Furthermore, this type of landscape is among the most conservative ones, and inside the caves many evidences (sediments, archaeology, palaeontology, cave dwelling fauna, etc.) that enable palaeogeographic, palaeoenvironmental and palaeoclimatic reconstruction can be found.
The example of the Island Sardinia (Italy) is illustrated: here almost 8 % of the territory is constituted of karstic areas where carbonatic rocks with ages ranging from Cambrian to Miocene crop out. More than 2500 natural karstic caves have been surveyed for a total length of over 320 km; 40 % of these are located in the Mesozoic limestones of Centraleast Sardinia and 30 % in the Cambrian Iglesiente Sulcis area in Southwest Sardinia. Other interesting karst landscapes are situated in the Northwest of the Island (Capo Caccia-Punta Giglio) and in the centraleastern part (Tacchi area). Geodiversity and biodiversity of these karst complexes give interesting information on local and regional palaeogeography, palaeoenvironment and palaeoclimate, and enables to define some of these areas extremely important geo-ecosystems of international interest
