Nature's Most Amazing Events

The summer melt of Arctic ice provides opportunities for millions of animals, but grave dangers for others, including polar bears.

An amazing look at the annual return of millions of salmon to the streams where they were born; the survival of North American grizzly bears depends on this natural event.

The cameras follow the moving story of one lion family's struggle to survive until the return of the great migration; as weeks turn to months, the pride members become frailer, and the number of cubs dwindles from seven to two.

A look at the sardine run, which happens each winter along the South African coast, and the predators that wait for them.

The great flood in the Okavango turns 4,000 square miles of arid plains into a wetland, drawing in millions of animals including elephants and hippos.

Every summer in the seas of Alaska, humpback whales, sea lions and killer whales depend on an explosion of plant life, the plankton bloom; it transforms these seas into the richest on Earth, but these animals may not survive to enjoy the great feast.