Arch

•The entire arch is in compression. And it can use materials that are not strong in tension.
===One of its disadventages relative to modern alternatives, such arch bridges are very heavy, requiring extensive foundations. They are also expensive to build wherever labor costs are high. ===

Blind Arch - A blind arch is an arch infilled with solid construction so it cannot function as a window or door.
===Natural Arch - Natural rock formations may also be referred to as arches. These natural arches are formed by erosion rather than being carved or constructed by man. ===