Southern Arizona is known for its desert climate, with very hot summers and mild winters. Northern Arizona features forests of pine, Douglas fir, and spruce trees; the Colorado Plateau; mountain ranges (such as the San Francisco Mountains); as well as large, deep canyons, with much more moderate summer temperatures and significant winter snowfalls. There are ski resorts in the areas of Flagstaff, Sunrise, and Tucson. In addition to the internationally known Grand Canyon National Park, which is one of the world’s seven natural wonders, there are several national forests, national parks, and national monuments.