The ICBM is a unit in Civilization Revolution.
This unit is essentially a single-use nuclear weapon. It can utterly devastate any one city, but that is the only one it will ever destroy, as it can only ever be built and used once. It can only be built after the construction of the Manhattan Project wonder. This is only available in the Modern Era, and can only be built in one city. It is suitably the most effective and rarest weapon in the game.
The ICBM can be shot 40 tiles away and will harm not only the tile it hits, but the eight tiles around it too.
This weapon cannot be created until the Manhattan Project wonder has been created first. The actual price of the weapon is fairly low at 40 production. Using the ICBM instantly reduces your culture level, shrinking your cultural borders, unless you have adopted the Despotism government.
A common misconception is that when you obtain an ICBM, you will not be threatened. Whilst this is true for the first few turns, other civilizations may claim that the use of nuclear weapons has no good in it and will declare war anyway.