In Bulgaria, nature leaves green legacy along Iron Curtain route Lush chestnut forests and verdant pastures cover the northern slopes of the Belasitsa mountain range in southwestern Bulgaria, part of a surprising legacy of the Iron Curtain which once cut across this region. Thirty years ago, barbed wire fences ran through here, dividing communist Bulgaria from neighbouring NATO member Greece as well as from the former Yugoslavia, which while also communist, had a more distant relation to Moscow.