Finally , Attenborough ascends 6.5 kilometres into the atmosphere in a hot air balloon .
The red - breasted goose migrates entirely overland , and so can stop for fuel every night -- unlike those that cross the open ocean .
Attenborough ascends 6.5 kilometres into the atmosphere in a hot air balloon .
The red - breasted goose migrates entirely overland , and so can stop for fuel every night -- unlike those that cross the open ocean .