Summit Lake is the highest park in the Denver Mountain Parks system. The site was designated a National Natural Landmark in 1965 because of its extraordinary characteristics. Despite its location in the alpine, the environment mirrors the arctic. Permafrost (permanently frozen ground), unique to the dry alpine tundra, is present, along with rare plants usually found above the Arctic Circle. The alpine tundra is arguably the harshest environment that supports life in the world. An extremely cold, dry environment, the land is consistently showered with intense sunlight and pummeled by high winds. Only living things with highly specialized adaptations exist here.