Chimney Rock National Historic Site , spiral sandstone formation west of Nebraska , USA showing an important landmark along the Oregon Trail . It is located about 5 km south of Bayard and consists of a 37 meter long needle on a cone-shaped hill. Overall, the formation rises 145 meters above the south bank of the North Platte River . First used as a landmark by fur traders in the early 19th century, it was a significant milestone on the Oregon Trail. For early westbound travelers, this meant they were approaching the end of the Great Plains and the beginning of the Rocky Mountains were approaching . The presence of a reliable Water Supply made it a popular campground for the pioneers. The visitor center features exhibits related to the westward migration. Chimney Rock was designated a National Historic Site in 1956.
After the war. the American army only kept two self-propelled anti-aircraft guns. the M16 and the M19. But when the Korean War broke out in 1950, the industry almost immediately got down to the study of a new anti-aircraft self-propelled gun, designated T141, which employed many components of a new