The Westbury White Horse carved on the hillside near Westbury in Wiltshire, England. Photo credit: tipwarm/Shutterstock.com
A large portion of Southern England is made up of chalk. This white limestone are the shells of tiny marine organisms that lived and died in the seas that once covered much of Britain some 90 million years ago. As time progressed, layers of calcium carbonate built up and got compacted into a solid layer of rock. Later, tectonic movements lifted the sea floor out of the sea and these became the magnificent downland in south of England.
Much of this chalk is hidden by a thin layer of soil and vegetation, except on the edges where the chalk is exposed to the sea, leading to such dramatic headlands as the white cliffs of Dover, Beachy Head and The Needles. For centuries people have been scratching away the topsoil to reveal the whitish layer of chalk to create gigantic works of art on the countryside. When the bedrock is not made of chalk, people have dug trenches and filled them with chalk brought from elsewhere. The artworks are usually made on the hillside so that they are visible from the distance. This is important, because often the chalk figures are so large they can only be appreciated from far away.