In May 1952 East Germany sealed its entire border with the capitalist west. Over the next 37 years 75,000 people would be arrested trying to flee the Communist East and hundreds would die in the attempt. Today the barbed wire and machine guns are gone and the old border has been transformed into a protected wildlife zone. It's a home to lynx, wolf and wildcat and a vital corridor for migrating birds and mammals. Mary-Ann Ochota begins her journey along the old border, meeting the people doing their bit to turn a birdwatcher's fantasy into the world's longest nature reserve.

(Photo: Mary-Ann Ochota walks the route of the Iron Curtain through central Germany)