Choose a walking route to meet your fitness level and keep an eye out in the woodland – this is one of the few places in England where you can still spot red squirrels. A section of Unesco-heritage listed Hadrian’s Wall – the Roman wall running coast-to-coast – goes through the south of the park. Take a glimpse at “some of the darkest skies in the world” at Kielder Observatory, which is open year-round, for a chance to spot the Milky Way and other astronomical wonders.