LIMA, PERU—First discovered 19 years ago, the massive, 5,000-year-old city of Caral is still being explored by archaeologists. Recent finds at what might be the earliest city in the New World have included a small public building on the outskirts of the site that was connected with the core area by a road. Archaeologist Ruth Shady, who heads the Caral Archaeological Area, says she and her team are at work on 11 other settlements that belong to the Caral period, which lasted more than 1,000 years.