After Hamburg joined the German Customs Union, it became necessary to create a free trade zone. From 1885 an entire neighbourhood around the Zollkanal was torn down to make way for the Speicherstadt warehouses. Now a UNESCO World Heritage Site, the 373 000m² complex still houses precious goods. With its rows of gabled brick buildings, Speicherstadt is a distinctive and architecturally harmonious area. Quite a few buildings have been restored and turned into museums.