"Bamberg, Klein-Venedig" von Ludwig Mössler
This card shows Little Venice, an row of 19th century fishermen's houses along the Regnitz River in the city of Bamberg in southern Germany. Bamberg managed to avoid being destroyed by bombs in World War II because there was an artillery factory nearby, and the Old Town of Bamberg, including Little Venice, is a UNESCO world heritage site. This card is a painting by Ludwig Mössler.
Instead of a stamp, it came with a postage label printed from the internet. Kinda cool.