Wisłoujście Fortress - Credit: Wikimedia Commons
Wisłoujście Fortress (, ) is a historic fortress located in Gdańsk by the Martwa Wisła river, by an old estuary of the river Vistula, flowing into the Bay of Gdańsk. The fortress is located close to the Wisłoujście borough, Westerplatte and the Port Północny (Northern Port). It is listed as a Historic Monument of Poland. Read more on Wikipedia
Source: en.wikipedia.org