The Bréau menhir, also called the Pierre qui tourne du Moulin Neuf or the Vinegar Stone, is a menhir located in Fief-Sauvin.
The building was listed as a historical monument in 1990.
The menhir is located a short distance from the left bank of the Èvre. It is made of greenish, Precambrian schist, infiltrated with quartz. Its height varies between 3.30 m and 3.50 m given the slope of the land. Seen from the front, the two sides meet slightly to form a wide rounded top. Seen from the west side, on its flat surface, it appears to end in a point.
The building was apparently the subject of an old excavation that revealed a wedge with bricks from the Roman era.
On the other bank of the Èvre, in the commune of Beaupréau, there once stood the Pierre Aubrée (Obrée, Au Bré), a granite menhir of which only the buried part remains, with an average diameter of 1.50 metres.
According to tradition, the menhir turns at the stroke of midnight. The stone is said to smell of vinegar.