A Cottage is a tile improvement that can be built by Workers immediately upon the discovery of Pottery. Cottages add Commerce to their tile. Cottages may be created on most flatland, and in addition, they may also be placed on grassland hills. Cottages are a relatively low-value tile improvement when they are first created, but they grow in value after many turns of being worked. They go through four stages of growth, becoming Hamlets, Villages, and finally Towns (though players refer to all of these things generically as "cottages").