The Chamonix valley and the Mont-Blanc mountains are an outdoor museum of the impact of the Little Ice Age on the landscape from the mid-sixteenth to the late nineteenth century, and the retreat of glaciers in the modern times, whether for natural causes or due to human activity. This tour guide first introduces to the theme of glaciers in a changing climatic context. Then it illustrates the field connections in a field trip to the Mer de Glace and its foreland in Chamonix.