The Netherlands has a coastline of over 400 miles but they have always been characterized by an uneasy relationship with the sea. Because of geomorphology that puts the country on average 5 meters below sea level, the Dutch urban planning, at all levels of government, has always questioned the need to defend themselves from river and marine flooding; over the centuries it has developed a pragmatic approach , enshrined in various national laws and in the establishment of the Ministry of Water Management, which has set as its main objective the defense of the territory from the water.