Peninsulas are landforms that are surrounded by water on three sides and connected to the mainland on one side. They can vary greatly in size and shape, and are often characterized by their unique ecosystems and biodiversity. Famous examples include the Iberian Peninsula in Europe and the Florida Peninsula in the United States. These landforms play a significant role in human settlement and culture, often serving as strategic locations for trade and defense. Peninsulas can also influence local climates and ocean currents, making them important for both natural and human activities.