Civil War Fortification at Barnesville - Credit: Wikimedia Commons
Civil War Fortification at Barnesville, also known as Fort Barnesville, is a historic American Civil War fortification located at Deer Run State Forest near Ellington, Reynolds County, Missouri. It was built in 1863, and consists of a horseshoe shaped redoubt. It measures approximately 150 feet long and 135 feet wide. (includes 50 photographs from 1998) Read more on Wikipedia
Source: en.wikipedia.org