The Florida Everglades

The Florida Everglades, lying within the tropical zone near the equator, is one of the largest freshwater marshes in the world, stretching from Lake Okeechobee 100 miles (160 kilometers) south to Florida Bay. Within its boundaries are also freshwater swamps and coastal (saltwater) mangrove swamps. In the northern portion of the Everglades is Big Cypress Swamp. This swamp covers 1,500 square miles (4,000 square kilometers) and gets its name from the many tall bald cypress trees that live there.

The Everglades were formed during the last Ice Age, which ended about 10,000 years ago. During this period, glaciers melted and sea level was raised, which flooded the area and turned it into a wetland. Under the water and soil is porous limestone rock formed during the last glacial period. This type of rock contains shells and skeletons of animals deposited in the sea. Hummocks (rounded hills...