Massive animal migrations are among nature's most inspiring events. Whether by wing, fin or hoof, the distance some creatures travel in search of a new habitat is paralleled only by what they endure to survive.
Migrations also play a vital role in our natural ecosystems — they are the veins and arteries of Mother Earth — and they are a reminder that the world's habitats are interconnected. Here's our list of the planet's greatest migrations. (Text: Bryan Nelson)