Planet Earth is a 2006 British television series produced by the BBC Natural History Unit. Five years in the making, it was the most expensive nature documentary series ever commissioned by the BBC and also the first to be filmed in high definition.[1] Planet Earth premiered on 5 March 2006 in the United Kingdom on BBC One, and by June 2007 had been shown in 130 countries. The series comprises eleven episodes, each of which features a global overview of a different biome or habitat on Earth. At the end of each fifty-minute episode, a ten-minute featurette takes a behind-the-scenes look at the challenges of filming the series.