I think this is the largest biplane I’ve ever seen.

At the time of its completion the Siemens-Schuckert R.VIII was the largest aeroplane in the world; (the Mannesman-Poll triplane was to have been much larger but was not completed before the Versailles Treaty came into force).

Ahh. That makes sense.

https://en.m.wikipedia.org/wiki/Siemens-Schuckert_R.VIII