Vale Maria do Meio is a cromlech, believed to date back to the fifth millennium BCE.

The cromlech is located in an area with a significant number of megalithic monuments. It is about 1.5km to the northeast of the Portela de Modos cromlech. The Almendres Cromlech, a major megalithic site, is about ten kilometers to the southwest.

The cromlech was identified in 1993. Excavations in 1995 identified 34 granite menhirs, which are predominantly ovoid in shape and have an average height of 1.74 meters. Suggesting an astronomical purpose, the stones form an east-west elongated arch, which is about 37 meters long and 25 meters wide.

Most of the stones are well preserved. Engravings of circles, horseshoes and lunar crescents have been found on two of the menhirs. In 1995, an attempt was made to understand the effort involved in the construction of stone circles. With the help of ropes, logs and 70 volunteers, it proved possible to raise most of the monoliths.