This programme marks the 70th anniversary of the creation of our national parks. Matt will be looking at the history of their formation, and he’ll be joining a diverse group of walkers recreating historic photographs from the mass trespasses of the 1930s. John is exploring the industrial history of Rosedale on the North York moors and meeting the modern day glassmakers following in the footsteps of 16th-century Huguenot artisans. Charlotte is in the New Forest looking at the pressures on the park caused by its proximity to big urban centres. Sean is in Pembrokeshire finding out how park authorities have engaged walkers in a citizen science project to record coastal erosion on their smartphones. Margherita is on Exmoor telling the story of long-forgotten 19th-century landscape visionary John Knight, who planned his own embryonic 'national park' back in the 1820s, and Adam is in the Trossachs finding out about the challenges of farming in a national park.