Here are some snapshots of heaters I ran across while traveling. The first is a kacheloven room heater in Ukraine. The next is a small woodstove in a local internet cafe in Bulgaria. The last is a room heater, common in better homes in the mid 1800's in Bulgaria. In the room behind the stove there was an equal masonry assembly, but without the feed port. The flue was ducted so that the exhaust traveled through the second room's stove before exiting up the chimney.