An 8,000-year-old stone calendar
On a gentle slope among cork and olive trees, the Almendres Cromlech consists of 95 granite monoliths arranged in a pattern that has tracked the sun and stars for millennia. This site is the largest megalithic complex on the Iberian Peninsula and one of the oldest in Europe, with its first stones erected around 6000 BCE. This initial construction phase, known as Almendres I, predates the first phase of Stonehenge by approximately 3,000 years.
The site evolved over thousands of years. The first phase during the Early Neolithic period involved smaller stones arranged in three concentric circles. Around 5000 BCE, during the Middle Neolithic, a larger, elliptical enclosure of bigger menhirs was added to the west. The final phase, around 3000 BCE, saw some stones repositioned, transforming the site into a complex double-ring structure for ceremonial use. The stones themselves are local granite, many now showing significant erosion, with heights varying from under one meter to over 2.5 meters. The entire complex measures approximately 60 by 30 meters. The site was largely forgotten until its rediscovery in 1964 by Henrique Leonor Pina, who was conducting geological surveys.
A Neolithic observatory
The specific arrangement of the Almendres Cromlech shows a sophisticated understanding of celestial mechanics. The layout of the dual ovals is aligned with the equinoxes; from the center of the complex, the sunrise on the spring and autumn equinoxes aligns perfectly with specific stones. The site's latitude of 38.55 degrees north also corresponds to the maximum elongation of the moon.
There are other astronomical connections. The nearby Menhir of Almendres, a solitary 4-meter-tall standing stone, is positioned so that it marks the sunrise on the summer solstice when viewed from the main circle. This suggests the entire area was integrated into a larger system for observing solar and lunar cycles, likely for agricultural or ritual purposes.
About a dozen of the monoliths feature carved engravings. These include small circular depressions known as cup marks, wavy lines, and crescent shapes. Several stones have more complex carvings. Menhir 48 displays a schematic human figure holding a crosier, or shepherd's crook. Stone 56 is considered a menhir-statue, bearing the representation of a human face. These symbols, while not fully deciphered, appear at other megalithic sites in the Alentejo region, showing a shared symbolic language among Neolithic communities.