0321 GMT November 20, 2019
As new imagery taken from NASA’s Landsat eight satellite shows, the reappearance of the ancient monument is owed to very low water levels in Spain’s Valdecañas Reservoir following a summer of record heat and drought across Europe, livescience.com reported.
Sometimes labeled the ‘Spanish Stonehenge,’ the Dolmen of Guadalperal is a large circle of about 150 standing stones, some more than six feet tall, arranged around a central, open oval. Archaeologists speculate that the structure was built in the 4th or 5th millennium BCE (possibly making it thousands of years older than Stonehenge in England). The mysterious megalith may once have supported a massive stone cap that enclosed the space for ritual uses.
One particularly large stone (a “menhir”) seems to mark the entrance. This rocky threshold is engraved with a human figure on one side, and a squiggly symbol on the other side that could represent a snake or the nearby Tagus River. If a waterway is indeed being depicted, that could make the stone one of the oldest maps in Europe, NASA wrote on its Earth Observatory website.
According to Atlas Obscura, the dolmen was first excavated in Spain’s Extremadura region, just east of the Spanish-Portuguese border, in the 1920s, but no research on the site was published until the 1960s. By then, the site’s fate was sealed; in 1963, former Spanish dictator Francisco Franco undertook a sweeping civil engineering program that involved flooding the valley where the dolmen stood. Suddenly, the dolmen sat at the bottom of the Valdecañas Reservoir, a man-made lake abutting a hydroelectric dam that continues to generate power today.
Since the creation of the reservoir, the tips of some megalithic rocks have occasionally pierced the surface of the water, but never has the entire site been revealed at once. Before long, with the rains of autumn and winter approaching, the stones will likely be submerged again. Local groups have petitioned to move the entire monument to higher terrain, so that the stones can be studied in open air and visited by the general public. However, some archaeologists worry that moving the monument could accelerate its decay, especially if the job is done hastily, in a race against the rising waters.