The Eden Project is celebrating 20 million visitors today with a challenge to find a Golden Biome and win a bumper basketful of top prizes.

Eden has calculated that its 20 millionth visitor since it fully opened on March 17, 2001, will arrive on Monday, April 9.

A miniature Golden Biome marked with the Eden logo and “20 million” will be hidden within the project’s site very early this morning and a series of clues will be released through the morning to visitors. 

The piece has been made out of clay by Eden designer Lou Thorn and lacquered with gold-coloured paint.

On the bottom of the Golden Biome is a mobile phone number and all the finder has to do is call that number as soon as possible, say “Golden Biome” and give their location to take delivery of the prize, which will be awarded on the day.

The clues will be given out every half an hour from 10.30am via the Eden Project’s Facebook page and Twitter  - @edenproject - and will also be written on a board at the entrance to the Biomes at the same times.

The only clues Eden is giving out in advance are that in order to find the Golden Biome no living things need to be disturbed and no soil trodden on.  Follow those clues and you could be on the right path.

The finder will win a basketful of gifts from the Eden Shop plus Joint Family Eden Project Membership, a pair of Eden Sessions tickets to a 2018 concert of their choice, lunch in the Mediterranean Biome for the family, and a ride for the family on the Hangloose Skywire which flies over the site.  

Eden chief executive Gordon Seabright said:  ‘We’re so grateful for the support of all our visitors over the years and it is wonderful to think that our 20 millionth will be coming through the doors on Monday morning.’