FLORIDA: The Calusa Indians, who ruled much of southern Florida in the pre-Columbian era, are known for their sophisticated engineering projects. These included artificial islands and canals at their capital of Mound Key. They also created large lagoons called watercourts out of shells and sediments. These enclosures, which date to the 14th century, acted as holding tanks, allowing the Calusa to trap and store large numbers of fish in the subtropical climate.