The route leaves Mértola, with its castle above the Guadiana, and heads east to the old São Domingos mine, an abandoned mining village. From there it runs north on the ER 265 to Serpa, a walled town in the Baixo Alentejo.
This is the Alentejo of wide horizons: cereal plains, holm-oak pastures, few villages and a lot of sky. The road is quiet with hardly any traffic. It crosses the municipalities of Mértola and Serpa.
It is about 55 km and just over an hour and a half without stops, with some 60 gentle bends. Altitude ranges from about 35 m to about 230 m. It suits an unhurried ride with stops at the mine and in Serpa.