The silo, stores food. In addition, you need at least 1 silo at all times to act as a drop off zone for your workers. If your food supply glows red, it means you have no more room to store food, and any leaves beng collected are wasted, build more silos to increase your capacity... or just use your food faster. Cost: 50 food Capacity: Stores 50 food Time: builds quickly Death: does not leave an opening when destroyed