PLANET EARTH Mountains
On the highest summits of our planet nothing can live permanently. The highest peak of all, Mount Everest, five and a half miles above sea level and still rising - the roof of our world. Of those humans who've tried to climb it one in ten have lost their lives. Those that succeed can stand for only a few moments on its summit.
The Nepalese call it “a mountain so high no bird can fly above it.” But each year over 50,000 demoiselle cranes（<法语>少女，中文翻译蓑羽鹤） set out on one of the most challenging migrations on Earth. To reach their overwintering grounds in India they must cross the Himalayas. By late morning ferocious winds are roaring past the peaks.
The cranes must gain height to avoid the building storm. They've hit serious turbulence. They must turn back or risk death. A new day and a new opportunity. The flock stay in close contact by calling one another. Weak from lack of food and water, they use thermals, rising columns of warm air, to gain height.
For many this is their first journey across the Himalayas. For some, it will be their last. The golden eagles have been expecting them. The eagles work in pairs to separate a young crane from the flock. It escapes the touches of one, and is caught by another.
But even a young crane is a heavy prize and the eagle has to struggle to control it. The mother can wait no longer - this is a desperate race against worsening weather. The rest of the flock battle on. In the ascent every wing beat becomes an exhausting struggle. At last they are over the highest barrier that lies in their way. But like all who visit the world of the high mountains they dare not linger.
