
Some of the oldest mountains in the world make up this small natural reserve. Once the home of the original inhabitants of Tandil, the reserve is comprised of natural rock formations sit alongside the ruins of man-made structures.
At the entrance, the Centro de Interpretacíon details the variety of species that visitors may encounter. Deer and snakes, native flora and exotic fauna, and even the odd puma, the bio-diversity of these 140 hectares is surprisingly varied. Although founded as a reserve in 1972, Sierra del Tigre remains isn't visited frequently, thus little has changed. Six kilometers outside of Tandil, the reserve features nature walks and beautiful viewpoints, which are easily ventured to alone.
Tandil was always identified with that marvel of the nature: the Moving stone of Tandil, whose weight is 100 ton. It is difficult to explain how it swings, nonetheless, keeping its balance on top of a hill which is 294 meters high. The stone collapsed in February, 1912 and it broke into three pieces which can still be seen on the foot of the hill.