This is the longest glacier in Europe at 23km long, starting south of the Jungfrau in the Bernese Oberland and descending into the Upper Rhone valley of the Valais.
On the horizon at the start of the glacier, you can just make out the Jungfraujoch, from where you can get an alternative view of the glacier looking back towards this viewpoint.
This photograph was taken in June 2008 from near to the top station of the Eggishorn cable car, and after scrambling along a rocky ledge I was able to reach this view, which is one of the best I have seen in Switzerland.

The Aletsch Glacier, which is a UNESCO World Heritage Site, is said to have retreated by 100m between 2005 and 2006.

Aletsch Glacier - Eggishorn visitor guide showing a virtual tour of 'Aletsch Glacier' linked to an interactive map with local and travel information. 360° panoramas from Wallis.