Built in 1853 by the mill-owner Titus Salt, Salts Mill was once the largest factory in the world by floor area, and the model village of Saltaire that grew up around it is now a UNESCO World Heritage Site. Since the looms fell silent it has filled with David Hockney galleries, a huge bookshop, design shops and a cafe. Entry is free and it’s a two-minute walk from Saltaire station.