The Zuiderzee played an important role in the economy of the Low Countries since reaching its largest size in the Late Middle Ages. It can be seen as a large traffic roundabout with intensive shipping, for transport and trade but also for fishing. This is because the Zuiderzee was very rich in fish and acted as a breeding ground for several different North Sea fish. However, its ubiquitous shallows, sandbanks and waterways that silt up also made it into a dangerous inland sea, where storms could wreak havoc. Many a ship was lost but remained preserved in the soft seabed. Since the creation of the polders of Flevoland mid-20th century this has allowed for the discovery and research of over 400 shipwrecks by maritime archaeologists. Sometimes surprising objects are found aboard, but the remains of the ships themselves are also a valuable source of information: about the shipbuilding practices of yesteryear, for example. The concentrated amount of underground shipwrecks makes Flevoland into the world’s largest ‘dry’ naval graveyard of its kind. The many objects recovered from these shipwrecks form a large part of the Dutch national maritime collection, housed by Batavialand in Lelystad.