The north-east part of Poland, with its area of over 60 000 square kilometres, is referred to figuratively as the Green Lungs of Poland, It extends from the Vistula Lagoon to the Bug River Valley, occupying ca 20% of Poland’s area. It is a land of unique natural values of international importance. It features 260 natural reserves, 17 national parks, 7 primeval forests, clean waters of the Bug, Narew, Biebrza Rivers and of lakes in the Suwałki region. The author focuses on the cultural values of this area being an ethnic „melting pot” of the Podlasie and provides the account of the past and present of such localities as Krynki, Wierszalin, Kruszyniany and Supraśl.