A large landmass that is smaller than a continent is referred to as an "island." Islands can vary greatly in size, from small landforms barely above water level to substantial masses that host diverse ecosystems. They can be found in oceans, seas, rivers, and lakes, and cultural characteristics often vary significantly among them. Some well-known islands include Greenland, the largest island, and smaller ones like the Galápagos or the Hawaiian Islands. Islands also play vital roles in biodiversity and can be critical for conservation efforts due to their unique habitats and species.