The German Oceanographic Museum in Stralsund is an institution with charisma - it has shaped the city‘s identity, grown over decades and become firmly anchored in the collective memory. It is one of the most visited museums in Germany and enjoys an excellent reputation and high standing internationally as an oceanographic institution. Under the umbrella brand of the German Oceanographic Museum, it combines four locations: the main building in the historic Katharinenkloster, the Natureum in the lighthouse at Darßer Ort, the Nautineum as an open-air museum, and the Ozeaneum on the harbour island, which was named European Museum of the Year in 2010. In 2017, an international architectural competition was launched, which was won by Reichel Schlaier Architects from Stuttgart. The aim was to develop the main building of the MEERESMUSEUM in Katharinenkloster into a contemporary museum in terms of both structure and function. The challenge was to integrate parts of the building and historical layers from different centuries and generations. Sensitive handling of the building fabric was essential, as the ensemble is one of the most important urban structures in the Hanseatic city of Stralsund and part of the UNESCO World Heritage Site. The jury praised particularly the concept of preserving, highlighting and revitalising the main attractions of the MEERESMUSEUM, which has grown over decades.