Rosans is a "perched village" around a Romanesque tower from the 13th century known as "Tour Sarrasine". This tower corresponds to the former fortifications that protected the burg from the endless fighting between Dauphiné and Provence.
In the Middle Ages, the burg of Rosans grew around this donjon. It is home to an exhibition hall, the reserves of the heritage centre and a terrace with a panoramic view.
Two sundials adorn the village, one of which is on the façade of the town hall. It bears the motto of the Turkheim family and the second a painted quotation from Jean Giono.