The White Cliffs of Dover are primarily made up of a type of limestone called chalk. Chalk is a soft, white, porous sedimentary rock that is composed of the skeletal remains of microscopic marine organisms such as coccoliths and foraminifera. The White Cliffs of Dover are one of the most famous landmarks in England and are located on the coast of southeastern England, facing the English Channel. The cliffs are formed from layers of chalk that were deposited over millions of years during the Cretaceous period, and have been shaped by erosion and weathering over time.