480 ha is the size of the Inselsee near Güstrow in North-East Germany.
By the way, there are many beaches, bays and places to swim along the lake. You can hike or bike along the shore – and for a comfortable break you will find two of our toilets there.
Source: https://insiderei.com/listen/tipps-in-guestrow-museen-inselsee-schloss
Photo: ABEREUS