The Cathedral Basilica in Pelplin is the former church of a Cistercian abbey – the monks arrived in Pelplin in 1276. The present church was built in the 14th century and is one of the largest brick Gothic buildings in Poland. It has been a cathedral since 1824, and in 2014 the former Cistercian complex was designated a Monument of History. The interior impresses with its rich furnishings, including a monumental, 25-metre-high main altar. We created a mobile app for Android and iOS phones as well as an audioguide system. The recordings lead visitors through the cathedral and present its history and most precious furnishings. The audio guide is available in Polish, English and German.