The Zeppelin-Staaken R.VI was a four-engined German biplane strategic bomber of World War I, and the only so-called Riesenflugzeug ("giant aircraft") design built in any quantity. The R.VI was the most numerous of the R-bombers built by Germany, and also among the earliest closed-cockpit military aircraft (the first being the Russian Sikorsky Ilya Muromets). The bomber was reputedly the largest wooden aircraft to be produced in any quantity during World War I, with only the Siemens-Schuckert R.VIII prototype bomber of 1918-1919 being larger, with the Staaken R.VI's wingspan of nearly equaling that of the World War II Boeing B-29 Superfortress, and somewhat less than the span of the Siemens-Schuckert R.VIII.