Houghton Mill is the last working watermill on the River Great Ouse, standing on an island near St Ives on a site that has milled grain for more than 1,000 years. The 18th-century building milled on an industrial scale in Victorian times; it came close to demolition before villagers saved it and restored it to working order. In season you can book a volunteer-led guided tour on selected days or wander three floors of machinery on a self-led visit, and freshly ground flour is sold to take home. Waterclose Meadows offer level riverside walks to St Ives, a campsite and water busy with paddleboards and canoes in summer. Dogs are welcome on leads in the meadows but not inside the mill or tea-room. Reviewers praise the enthusiastic volunteers and the riverside tea-room. Tips from regulars: the car park is small and pay and display for non-members, so arrive before midday on a weekday, and guided tours must be booked ahead.