A natural arch is a geological formation where a rock structure has an opening or passageway created by erosion. This process often occurs in areas with softer rock layers that wear away over time, leaving a bridge-like structure. Natural arches can be found in various landscapes, including deserts and coastal regions. These formations are typically made of sandstone, limestone, or granite and can vary in size and shape. Famous examples of natural arches include Arches National Park in Utah and Delicate Arch, which attract many visitors due to their unique beauty and geological significance.