The Vogelsberg is about 19 million years old and is Germany 's only shield volcano and the largest basalt formation of Central Europe . It consists of many layers which fall downward from their peak in ring-shaped terraces to the base . Arising approximately 19 million years ago , the Vogelsberg , Germany 's only shield volcano , is also Central Europe 's largest basalt formation , consisting of a multitude of layers which , having flowed over each other , fall downward from their peak in ring-shaped terraces to the base .