Mont Blanc, the highest mountain in the Alps; and the subject of a disagreement between France and Italy.

This map was published by the Institut Géographique National, and it depicts a French territorial claim which extends 850 metres (2800 feet) over the mountain summit. However, Italy claims that the border is defined by the watershed. Maps produced by Istituto Geografico Militare draw the border across the summit, dividing it between the two countries.

The precise alignment of the border has been argued from 1796 to the present day!