During the Second World War, the Soviets commissioned the Dark Horseman project to create nuclear weapons. To house them, they made missile silos. These structures were mainly built underground to better contain the deadly weapons they produced. In an attempt to hide these silos from prying eyes, the Soviets painted all silos a dark green to blend into the grass and foliage in temperate climates, and white to blend in with snow in cold climates.
Most of these structures were located at the Dark Horseman facility, and they were shut down by Allied forces before the Soviets were able to launch nuclear strikes on the major cities of Allied Europe. Nevertheless, Soviets managed to secure remaining missile silos on their soil, and one was present during the final assault on Moscow.
They were generally not allowed to be constructed by regular commanders with very few exceptions. The Allies were also reported to build missile silos on a few occasions. Both sides' protocols dictate their facilities must be under close-and-constant monitor of specialized personals and equipments located within a secured tech center, and only one can be build in order to avoid any possible chain reaction.
After the war, the Soviets began using a different Nuclear Missile Silo, which sacrificed subtlety for reinforced armor and morale-incitement designs. The Allies still possessed nuclear weapons as well but their nuclear weapons were crippled at the very onset of the war when Yuri mind controlled the Allies' nuclear silo operators causing the nuclear ICBMs to explode in their silos. They resorted to Einstein's Weather control device as their offensive superweapon. The services of Weather control devices will be asked one more time in the war against Yuri as the latter's plan left Allies no "times" to reproduce their nuclear arsenals.
In the Red Alert campaign, only Soviets use missile silos. However, the Allies can also build them in skirmishes. The nuclear weapon is only devastating towards infantry, light vehicles and structures but bad against tough armored units.