Geology
The cliffs are composed mainly of soft, white chalk with a very fine-grained texture, composed primarily of coccoliths, plates of calcium carbonate formed by coccolithophores, single-celled planktonic algae whose skeletal remains sank to the bottom of the ocean during the Cretaceous and, together with the remains of bottom-living creatures, formed sediments. Flint and quartz are also found in the chalk. White cliffs like those of Dover are also found on the Danish islands of Møn and Langeland and the island of Rügen in Germany. In a 2005 poll of Radio Times readers, the cliffs were named as the third greatest natural wonder in Britain.
The cliff face continues to weather at an average rate of 1 centimetre (0.39 in) per year, although occasionally large pieces will fall. This occurred in 2001, when a large chunk of the edge, as large as a football pitch, fell into the channel. A further large section collapsed into the English Channel on 15 March 2012. Visitors are, therefore, urged to remain well away from the cliff edge.
Read more about this topic: White Cliffs Of Dover