The Cerbaie Hills is a very rich area of environments with valuable rare plant species, making it one of the places with the highest biodiversity of Tuscany. The Cerbaie Hills are made of a tableland (maximum elevation of 115 meters above sea level), located between the Arno Valley southwards and the Marshes of Bientina and Fucecchio, respectively, westwards and eastwards. The short streams that cover the tableland have cut through the sands and conglomerates substrate deeply enough to create narrow valleys, called “vallini”, where micro-climatic conditions allowed a varied floral presence and the survival of wrecks plants groups from cold climate, even at very low elevations. The Bientina Marshes is an important wetland remainder of a larger lake (the former Lake of Sesto) between the Cerbaie Hills and the Mount Pisano. In many areas of the marshes (Botronchio, Grugno) highly complex environments endure, composed by valuable plants, became rare by now. In this slight and seemingly ordinary plot of hills, then, suddenly sprout carnivorous plants (Drosera corsa), existing, in the world, only in a few square meters near Poggio Adorno, or community of gentians, once found in swamps of half Italy, now can be found, on the peninsula, only in a grassy meadow not far from Galleno, or even water violets survived today, not without hard difficulties, in small lakes in the depths of remote “vallini” on the Cerbaie Hills ... Or again Sphagnum peat bogs, last glaciation environments remain, surviving only in the most isolated caves of forests, grasslands or rivers ... in the midst of which tropical ferns (Felce florida), dating back to the Tertiary period, often seek surprisingly refuge. And furthermore, the many swamps (such as Botronchio), ponds, lakes and water sheets in which forests of black alder put down roots, where multitudes of absolutely valuable species sprout, by now hidden in dark caves, such as the humble Hydrocoyle vulgaris, the nearly rarefied Carex elata, the almost invisible Ophioglossum vulgatum... And again, as in a never-ending list, the expanses of Leucojum vernum, Galanthus nivalis, Allium ursinum, Narcissus poeticus. Regarding the animal’s presence, it is evident that the morphology of the Cerbaie Hills and its many valleys and wetlands is particularly suitable for the proliferation of amphibians: common toads, tree frogs, frogs, crested and marbled newt, usually spotted in damp woods. Even reptiles are widely represented. Worthy of note is the large number of birds, especially Herons (Ardeidae) and Waders (Limicola), - including the now rare black-winged stilt (Himantopus himantopus) - often nesting or wintering in the adjacent swamp areas (Bientina Marshes). These outstanding emergencies, in many cases recoverable within environmentally valued habitats, make this part of Tuscany unique, on the climate border between the cold-humid Central European area and the warmer and arid Mediterranean area, enough to recognize it among the SICs (Sites of Community Importance). To encourage the enjoyment of this beautiful area, a network of 10 trails were designed to surround (Great Ring of the Cerbaie Hills 66,1 Km, route 200) and cross (routes 201-209) the many places, naturalistically and scenically important, which can be found represented in detail in the Hiking Network Map of the Cerbaie Hills.