Well, to put it simple, the An-12 has been called the Soviet “Hercules.” The An-12 was a military medium-lift cargo aircraft developed from the underpowered An-8 via the flawed An-10. Neither of its two so-so forebears presaged its substantial success. Mind you, not in the same league of the Hercules, but close enough. Circa 1250 were produced, and a considerable number of them are still in service with military forces and in the civilian market. Furthermore, the Chinese version of the An-12 (Y-8) is still in production.
Gorgeous early in service photo. Soviet paratroopers were regular users of the An-12s. Notice the defensive armament which consisted of a stunning DB-65U powered turret with its two 23 mm Afanasyev/Makarov AM-23 cannons.