THE National Trust is to build a visitors' centre at Langdon Cliffs, part of the 5.5 miles of the White Cliffs of Dover owned by the trust. A competition for the centre was won by the architects Van Heyningen and Haward. The building will be made of timber and will feature a turf roof sporting wild flowers in spring and summer. The building will house an information centre, with a cafe and shop. This intriguing new landmark will be invisible from the Channel; it is to be located on the lower slopes of an existing car park.