Planet Earth I, II & III are a series of nature documentaries narrated by David Attenborough. The first series was produced by the BBC Natural History Unit, airing in 2006. 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. By June 2007 it had been shown in 130 countries. There have been 3 series to date with Planet Earth II airing in 2016 followed by Planet Earth III in 2023.