Formed some 20,000 years ago, this giant volcano crater lake is one of Nicaragua's most beautiful natural landmarks. Tropical dry forests surround crystal-clear waters, making it a place of great serenity and incredibly diverse wildlife, including iguanas, hummingbirds and howler monkeys. Although the area is a protected reserve, you'll find some excellent eco-friendly lodges around the shores of the lake, and there are great opportunities for hiking, swimming, kayaking and diving.