Even after the forts had lost their status as a defence system in 1950, they remained out of bounds for civilians because they still fell under the Ministry of Defence. With the peace and quiet that has reigned there for years, many former defence works have become nature areas where plants, birds and other animals can thrive. Various rare plants grow on and around the forts, having become scarce in the
man-made agrarian landscape. In many places the Defence Line of Amsterdam has become a sanctuary for all sorts of summer birds.

The Ministry of Defence gradually disposed of most of the forts and other parts of the Defence Line of Amsterdam after 1960. The restrictions in the ‘restricted rings’ were raised as well, which in several cases resulted in the expansion of residential areas and business parks. Nevertheless, the circular defence line has remained clearly recognisable. In the spring of 2004 the Defence Line of Amsterdam was designated a national landscape by virtue of the Belvédère project and the Nota Ruimte (policy document on spatial planning). National landscapes are areas with internationally rare or unique and nationally characteristic landscape qualities, in combination with special natural, cultural-historical and recreational qualities. The Nota Ruimte states that they must be preserved, constantly managed and, wherever possible, enhanced. The natural qualities reveal themselves in the special flora and fauna already mentioned, which has lead to nature conservation. The province of Noord-Holland is responsible for working out the policy for National Landscape, ‘The Defence Line of Amsterdam’. The province also wants to improve the recreational qualities of the Defence Line of Amsterdam, for instance by making the Defence Line more clearly recognisable, by plotting new bicycle and hiking routes, and by organising an annual public event. Today, many parts of the Defence Line of Amsterdam are managed by nature administrators, like the Dutch Forestry Commission and Natuurmonumenten (Dutch Nature Conservation Organisation). Other forts have been given a public-oriented or economic use. The Defence Line of Amsterdam therefore has an important dual purpose, both now and in the future: as a sanctuary for nature and as a place to experience cultural history.