The Russians love things big. They also don't let silly things like gravity and drag get in the way, dammit. We've only limited data on the K7 Flying Fortress, but this hasn't stopped Russian enthusiasts from rendering personal Nazi-UFO-killing versions.
From what we know in the limited drawings and photos at the end of the gallery above, the original K7 only had six BMW engines but they decided to switch to Soviet-built engines (that's thinking ahead!) so they added a seventh engine because Soviet engines sucked. Approximately 25 passengers and crew set themselves up inside the huge wing or hung out inside the train car-sized landing gear.
Enjoy the renderings above as they get a little crazy...