Blohm & Voss Ha 139

The Blohm & Voss Ha 139 was a four-engined, long-range flying boat produced in the 1930s and characterized by its inverted gull-wing wing configuration and twin-tail empennage. Used as an airliner and mail plane by Lufthansa on transatlantic routes between 1937 and 1939, the Ha 139 was at that time one of the largest flying boats ever built. Source: Wikipedia