These famous White Cliffs of Dover in Kent UK, sits opposite France across the Strait of Dover. The white is from the chalk and the black is flint. It is called the White Cliffs as it stretches some 13km across the coastline and the white chalk surface can be seen miles away. However, the constant erosion has lead to the flint becoming more apparent in sections of the cliffs nowadays. This part of UK is so near to France, when I came, my mobile actually picked up the signal from France and put me on roaming!
