What is Natural arch?
[[File:Delicate_Arch_LaSalle.jpg|thumb|right|[[Delicate Arch]] in [[Arches National Park]], [[Utah]], [[United States]]]] A '''natural arch''' is a natural [[rock formation]] where an [[arch]] has formed with an opening under the arch. It is also called a '''natural bridge''', or (less commonly) '''rock arch'''. Natural arches commonly form where inland cliffs, [[Cliffed coast|coastal cliffs]], [[Fin (geology)|fins]] or [[Stack (geology)|stacks]] are [[Erosion|eroded]] by the [[sea]], [[River|rivers]] or [[weathering]]. Most natural arches are formed from narrow fins and sea stacks that is made up of [[sandstone]] or [[limestone]]. {{Geography-stub}} [[Category:Rocks]] [[Category:Landforms]]