The mammoth task of cleaning the 8-storey cocoon building in the Natural History Museum's new Darwin Centre, was completed this week.
Abseiling cleaners took to the skies making sure the 65-metre-long building was sparkling clean for the opening on 15 September.
'It has been a challenge to organise the cleaning of the cocoon,' says Museum Customer Services Manager Sarah Ray. 'However, it is now complete and we are happy with the outcome.'
The cocoon gets a vacuum clean
The cleaners had to be specially trained to work in the cradle that carried them around the cocoon's surface, covering 3,500 square metres.
They began at 5am each day, setting up the cradle, and doing the bulk of the cleaning while temperature around the top of the cocoon exterior was still cool. It took 2 people 3 days to complete.
The cocoon is made of concrete and is the largest sprayed concrete curved structure in Europe.
Its surface is hand-finished polished plaster, bound in steel channels resembling the silk threads of a real cocoon in nature.
The new Darwin Centre building is designed by internationally renowned C F Møller Architects of Denmark. Work began in June 2006 and finished in September 2008.
The magnificent cocoon structure will protect and house the Museum's 20 million plant and insect specimen collections.
The world-class storage includes 3.3km of new mobile storage cabinets and tight temperature, light and humidity controls.
Around the central cocoon are state-of-the-art scientific research facilities where hundreds of Museum scientists work on cutting-edge research.
The public will be able to interact with them, getting an insight into their work, whether it's collecting and naming new species or organising collections that are being used to help study malaria or monitor climate change.
The abseiling cleaners were from DMW window cleaners, contracted by the Museum's housekeeping company Sherwood Cleaning Group.