One's sense of perspective is very poor when gazing at Grossglockner Glacier.  The immensity of it fools the eye so that it seems closer than it actually is.  The dark mountain about dead-center in the picture is 5 miles away.  The ice field is more than a quarter-mile below us.
The glacier itself is receding at about a foot per year.  In a thousand years, it will no longer exist.
I had the same sense of insignificance looking out across Grossglockner as I had when I gazed across the Grand Canyon, an "uncomfortable sense of immensity", not to mention the humbling experience of recognizing something too large to be easily comprehended.