With a surface area of 40 km2 and a length of 7 km, this is France’s largest glacier.
Its width varies from 700 to 1950 metres and the thickness of the ice is on average 200 metres, and sometimes exceeds 400 metres.
The Mer de Glace extends over a difference in level of 2500 metres, between the altitudes of 3900 m and 1400 m. Read on further here