Necessity of creation of aviation transport system for the project of a reusable spaceship "Boorun" (Snow-storm) was the reason of construction An-225.
At present An-225 is the heaviest and load-lifting plane, when or rising in air. The unique plane surpassing An-225 on wingspan, it Hughes H-4 Hercules which rose in air only once.
It is developed in a bureau of O.K.Antonova (Kiev, Ukraine).
Once I saw this plane when it did a turn, the angle was huge, speed was slow, looks like it will fall, it's very big plane, it's true =)
see also largest vehicle in world