Currently the world's largest aircraft, the first Antonov An-225 Mriya (meaning "Dream") prototype flew on 21 December 1988. It was designed and built by Antonov Design Bureau (headquarters in Kiev, Ukraine), known for their outstanding achievements in producing heavy transport aircraft. It is the largest aircraft to ever takeoff more than once.
Capable of transporting oversized objects externally, the An-225 was designed mainly to transport the Russian space shuttle "Buran" and its components from a service area to a launch site, although the Antonov bureau is looking for possible commercial applications for the enormous aircraft.
Construction of the An-124 provided the basis for the new aircraft with Antonov using many of the same components to keep cost and development efforts down. Although the basic configuration is the same as the An-124, the An-225 is longer, has no rear ramp/door assembly, and incorporates a 32-wheel landing gear system (two nose and fourteen main wheel bogies, seven per side, each with two wheels). The Mriya is not a military aircraft, however, it packs a great potential for military use as a super-heavy transport, it is capable of airlifting cargos that no other aircraft in the world is capable of.
As of this posting, only one An-225 has been built. There are rumors that the European Space Agency has plans to launch the unmanned British HoTOL (Horizontal TakeOff and Landing) from the An-225, though these rumors appear to be unfounded.