Variant 512/B is a short connecting path that links trails 511 and 512, which almost touch in the Is Ollastus area, on the upper part of Monte San Giovanni. This is a very interesting area from a geological, paleontological, and archaeological point of view. Connecting the trails is useful for customizing routes and diversifying them during different excursions. In the Is Ollastus area, which takes its name from the highest peak of Monte San Giovanni (431 m), there are traces of the Santa Barbara well (one of many with this name) and an ancient church dedicated to Saint John the Baptist.
