user: Extract the names of the Planet Earth series, and separate them with a comma.

Input:
Planet Earth (2006)
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.

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 has 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.

Planet Earth: The Future (2006)
Planet Earth: The Future is a 2006 BBC documentary series on the environment and conservation, produced by the BBC Natural History Unit as a companion to the multi-award-winning nature documentary Planet Earth. The programmes were originally broadcast on BBC Four immediately after the final three episodes of Planet Earth on BBC One. Each episode highlights the conservation issues surrounding some of the species and environments featured in Planet Earth, using interviews with the film-makers and eminent figures from the fields of science, conservation, politics, and theology. The programmes are narrated by Simon Poland and the series producer was Fergus Beeley.

Saving Planet Earth (2007)
Saving Planet Earth is a season of nature documentaries with a conservation theme, screened on BBC Television in 2007 to mark the 50th anniversary of its specialist factual department, the BBC Natural History Unit.

The series featured films contributed by a number of celebrities on the plight of various endangered species, and coincided with the launch of the BBC Wildlife Fund, a charitable organisation which distributes money to conservation projects around the world. The television series culminated in a live fundraising telethon on BBC Two, hosted by Alan Titchmarsh, which raised over £1 million for the charity.

The BBC broadcast a second live telethon in 2010. Wild Night In was presented by Kate Humble, Chris Packham and Martin Hughes-Games and featured conservation projects which had benefited from the support of the BBC Wildlife Fund. This helped to raise a further £1 million.

Planet Earth Live (2012)
Planet Earth Live is a live action nature documentary screened on British television. Produced by the BBC Natural History Unit and broadcast in May 2012, the programme was presented by Richard Hammond and Julia Bradbury.

Planet Earth Live featured real-time footage of young animals from five continents throughout the month of May. Broadcast three times per week, teams of nature experts and documentary makers monitored the activity of animals in their area, reporting back on the day’s events. Animals featured included meerkats in the Kalahari Desert, American black bears in Minnesota, lions and African bush elephants in East Africa, toque macaques in Sri Lanka, gray whales off the coast of California, polar bears in Svalbard and giant otters in Peru.

The programme was shown in May 2012 on BBC One in the United Kingdom and was broadcast in 140 countries in total, making it the most ambitious global wildlife series the BBC had ever undertaken. In the US it was retitled 24/7 Wild and aired on NatGeo Wild; in South Africa, Asia, Australia, Italy, Nordic countries, New Zealand and Poland it was shown on BBC Knowledge; and in India on BBC Entertainment.

Planet Earth II (2016)
Planet Earth II is a natural history documentary series, produced by the BBC as a sequel to the highly successful Planet Earth television series, which aired roughly a decade earlier, in 2006. The series was presented and narrated by Sir David Attenborough with the score composed by Hans Zimmer.

The first trailer was released on 9 October 2016, and the series was broadcast in November 2016 (United Kingdom) on BBC One and BBC One HD. Planet Earth II is also the first television series that the BBC have produced in Ultra-high-definition (4K).

Planet Earth III (2023)
Planet Earth III will be the third part in the Planet Earth trilogy. It is set to release in 2023.

assistant: Planet Earth (2006), Planet Earth: The Future (2006), Saving Planet Earth (2007), Planet Earth Live (2012), Planet Earth II (2016), Planet Earth III (2023)