Mysteries of Migration

Imagine driving over a hill and seeing hundreds of zebras or a thousand wildebeest. Anne and Steve were lucky enough to witness this spectacle in the Serengeti. Their expert guide, Moses Augustino Kumburu, describes the Great Migration.

Thousands of sandhill cranes gather each fall on the banks of the Wisconsin River before they head south for the winter. Anne and Steve visited the Aldo Leopold Foundation in Baraboo, Wisconsin to witness this migration firsthand, along with their guide: wildlife ecologist Stan Temple.

Science journalist Sonia Shah, herself the child of Indian immigrants, has long been fascinated with the way animals, people and even microbes move. Speaking with "To The Best Of Our Knowledge," she says migration is both a crisis and an opportunity.