There is another opportunity to visit the unique Bainton Heath which is not open to the public.
A guided walk on Sunday, July 21 will give you the chance to see the unique content of this site, which includes a small wood and a large pond.
It is a former landfill site filled entirely with fly ash from northern coal-fired powerstations and the railways in the 1960s.
As a result many species of moss and lichen grow there which are not natural to Cambridgeshire – but are more northerly species.
The landfill area has grown over with dense scrub to the north gradually thinning out to open grassland in the south with some bare patches with lichens growing directly on the fly ash.
It is surrounded on three sides by mature mixed woodland with a good variety of large trees and shrubs.
It is currently the home of National Grid and supports two electricity distribution systems and a sub-station. Ironically, the tall pylons have become a home for wildlife.
As a result it is not open to the public and visits can only be made there for events like this one.
If you would like to take part please meet at the Torpel site at 2pm. The plan is to drive from there to Bainton in as few cars as possible.