The Little Venice sports centre in central London is covered in sedum to absorb carbon dioxide and provide insulation.
The building also has rooftop wind-catchers instead of air conditioning, along with six solar panels.
The centre was designed by Mark Hewitt and David Boyd of LCE Architects.
Westminster City Council has partly funded the scheme, along with £1.6m from Sport England, Skills Active, the Big Lottery Fund and the John Lyon's Charity Trust.
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