The Mont Blanc de Cheilon is a 3’870 m high mountain in the Pennine Alps and forms the southern end of the Val des Dix.
First ascent: 11.09.1865 by Jakob Weilenmann and J. Felley (Swiss).
Switzerland 1985The Grande Dixence Dam is a 285 m high gravity dam. The dam's crest reaches an altitude of 2'365 m. It is this thirdhighest dam in the world. The highest dam in the world is the Nurek Dam in Tajikistan (300m) and the second highest is the Xiaowan dam in China (292 m).
São Tomé and Príncipe 2008
The illustration of the sheet is showing the Grand Dixence dam, Mont Blanc de Cheilon (behind clouds), La Ruinette and La Luette.The four stamps are showing: