In the C13th the Teutonic Knights set up what was to become one of the largest castles in the world. When they got too big for their boots the Polish kings made it their headquarters and later still the Prussians took it over. It was heavily damaged in WW2 in fighting between the Germans and Russians. Today, however, it is a World Heritage site and is being restored beautifully. The Visitors’ Centre, maps and audio guide make the visit very enlightening. The tempestuous and varied history of the site is well presented. My one quibble would be that the museum superintendents tend to patrol around like prison guards. A few lessons on PR wouldn’t go astray. I realise they have a treasure to protect but this can be done in a far more positive way.