Emperors and kings, chinstraps and adelies - the penguins of Antarctica all make their home in one of the most unforgiving environments on Earth. Their life has always been a constant struggle to survive, but their biggest challenge is yet to come. As the climate changes, long-established territories are being invaded and traditional nesting colonies are being disrupted. How will these extraordinary birds deal with the full effects of global warming?

Sunday, 4/27/08 from 8-9 p.m. ET
Thursday, 5/1/08 from 4:30-5:30 a.m. ET