Archaeologists working high in the Peruvian Andes have discovered the oldest celestial observatory in the Americas — a 4,200-year-old structure marking the summer and winter solstices that is as old as the stone pillars of Stonehenge. The observatory was built on the top of a 33-foot-high pyramid with precise alignments and sight lines that provide an astronomical calendar for agriculture, archaeologist Robert Benfer of the University of Missouri said. The people who built the observatory — three millennia before the emergence of the Incas — are a mystery, but they achieved a level of art and science that archaeologists say they did not know existed in the region until at least 800 years later. Among the most impressive finds was a massive clay sculpture — an ancient version of the modern frowning ‘sad face’ icon — flanked by two animals. The disk, protected from looters beneath thousands of years of dirt and debris, marked the position of the winter solstice. ‘It’s really quite a shock to everyone … to see sculptures of that sophistication coming out of a building of that time period,’ said archaeologist Richard Burger of Yale University’s Peabody Museum of Natural History, who […]