Built over several different periods between 5000 and 4000 BCE, the Almendres Cromlech are the finest example of Neolithic structures on the Iberian Peninsula, though it remained undiscovered until 1966.

The site consists of several classic megalithic structures, primarily cromlechs, and menhir stones. Arranged in patterns of two concentric rings – an eastern circle and a larger oval in the west – the 95 almond-shaped stones seen today represent a gradual process of accumulation and redistribution over time. 

The smaller ring to the east is the oldest section of the site, constructed during the early Neolithic period circa 6000 BCE, while the western oval ring is thought to have been built during the Almendres era 5000 BCE. During a third period around 3000 BCE, many of the stones seem to have been repositioned to better align with the moon, sun and stars.

As is common with such ancient sites, the purpose of Almendres Cromlech remains unknown. With the stones' final repositioning to be in-line with celestial bodies, geometric patterns already found at Almendres Cromlech were strengthened further, making the intentionality of the stones' presence and arrangement undoubtable, even if the deeper rationale and rituals contained therein remain a mystery.