One of the most beautiful documentaries about the wild life and earth that I have ever seen is the series of documentaries made by BBC. It called Planet Earth and Blue Planet.
The seines are amazing; from North Pole to South Pole they recorded unique and fantastic seines; from intact places that only few humans have ever been there, from the animals that rarely have been seen in the wild. What really astonished me is how these people filmed these. For each section of the documentary there is a diary part which explains how the crew spent months or a year at different places to capture unique shots. For example it shows how two camera men spent one year at South Pole to record unbelievable endurance of male penguins during the bitter and cruel winter of the pole; to record how the mother polar bear raise her two babies , how a young and starving male polar bear fight for his life.
If you love nature these DVDs are MUST SEEN for you.