The Kremlin reduces the cost of hurrying production and increases its city's chances of generating Great Spies. Maximizing gold is the key to success with the Kremlin. Putting the gold slider to 100% for a few turns will provide plenty of money for rushing soldiers or buildings with - particularly useful for fast city development or when a unique unit is available. While this move will set you back a few turns in technology, the advantages may far outweigh the negatives.