The Blue Ridge Mountains are one of three parts within the Appalachian Mountains and stretch from Georgia to Pennsylvania. The mountains began forming 400 million years ago during the Silurian Period due to previous versions of North America and Europe colliding.To the east is the Blue Ridge Escarpment, a steep uplift in earthen material forming the slope of the mountains, and to the west is the Valley and Ridge portion of the Appalachian Mountains. These mountains were once some of the tallest in the world and are still home to the tallest east of the Mississippi with Mt. Mitchell reaching 6,684 ft.