In the 1930s the Russian army was obsessed by the idea of creating huge airplanes. The images below are of a super-sized Russian airplane, the K-7 heavy bomber, built during the 1930s. The plane flew 11 times before crashing and killing 15 people. The designer, Konstantin Kalinin, wanted to build two more planes, but the project was scrapped. Later, Stalin had Kalinin executed. Evidently, it was not good to fail on an expensive project under Stalin.
The plane had propellers on the back of the wings, and 12 engines facing front. The size would be roughly equivalent to the Empire State Building on its side, with cannons.
At the time this plane was built jet propulsion had not been implemented, so the plane was engineered to have as many propellers as possible to help carry the huge flying fortress into the air.
Not many photos were saved from the era when these kinds of planes were built because of the high secrecy levels of such projects, but the photos reveal how remarkable these planes were.