(..) of the giant Baltoro glacier in the Karakoram mountains of Pakistan. It's the biggest mountain glacier on Earth - miles long and over miles wide. This huge ice-filled valley is so large it's clearly visible from space. This is the greatest concentration of peaks over miles high (..)

(..) opened by melt water as it plunges into the depths of the glacier. Like the water running through it, the ice itself is constantly moving, flowing down the valley with unstoppable force. Alpine glaciers may seem immense, but they're dwarfed by those in the great ranges that divide the Indian (..)