Countryfile - Green Space Dark Skies: Matt Baker introduces a special episode that comes from all four corners of the UK. Ben Nevis, Slieve Donard, Yr Wyddfa and Scafell Pike – the highest peaks of our four nations are the breathtaking backdrop for a massive art installation. Hundreds of volunteers, or 'lumenators', with specially designed bespoke lights, head for the peaks for this ambitious project celebrating access to and custodianship of the countryside.