High in the mountains snow falls. As it comes to rest on the frozen slopes it become part of an ancient glacier. Over the course of 100 years the glacier will flow down the valley, changing the landscape around it. Using field recordings from deep within glaciers, along with the sounds of the natural world around them, this programme charts an imagined journey of snow and glacier from mountain top to valley floor. Over the course of that journey we hear the sound world change and the increasing impact of human activity on the landscape - the wilderness of the high slopes replaced by the noise of tourism and traffic. There is an irony to the fact that the people who choose to visit the mountains because they love them are also contributing to their changing environment. These unique glacier recordings have been made by Ugo Nanni, researcher at the University of Oslo who specialises in the stability of Arctic glaciers, and field recordist Clovis Tisserand. Producer: Barnaby Gordon