Stora Alvaret

Stora Alvaret, meaning the Great Alvar, is a barren limestone terrace on the southern half of the island of Öland in Sweden, within Mörbylånga Municipality. It stretches about 40 kilometers in a dagger like shape up to 10 kilometers wide, covering more than 260 square kilometers and over a quarter of Öland's land area, making it the largest alvar in Europe. Its limestone bedrock formed roughly 500 million years ago on an ancient sea floor rich in fossils, was later shaped by glacial erosion during the ice ages, and was exposed when Öland itself rose from the Baltic Sea about 11,000 years ago as glacial pressure lifted. A soil layer no more than two centimeters deep, built up by plant colonization and wind blown sediment over the bare rock, leaves most of the limestone surface exposed.