The 30-foot summit of Mound Key is a stark contrast to other, low-lying mangrove islands dotting Florida’s Estero Bay. The artificial island, created from layers of countless shells, bones, and other material, was built by the Calusa people at least a thousand years ago. It served as their political and cultural seat well into the 1700s. At its highest point, a grand hall large enough to hold 2,000 people overlooked an urban center on par with contemporary Aztec city-states. The Calusa kingdom held political influence over southwest Florida for thousands…
