Who are we?Welcome to a world-class visitor destination in a UNESCO World Heritage Site. The Sill is the UK’s National Landscape Discovery Centre at Once Brewed in the Northumberland National Park. The building is the result of an innovative partnership between Northumberland National Park and YHA England and Wales. The Sill is a showcase of local pride and passion. It features exhibitions, learning and event spaces, a local food café, a brand new Youth Hostel, rural business hub, and a shop specialising in local crafts and produce.